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New session has begun in
math111e_Room1.
Tuesday, April 4, 2006 4:21pm
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*+**** Ann--Willem entered
math111e_Room1. Tuesday, April 4, 2006 4:21pm
*+**** Bridget--Tully entered
math111e_Room1. Tuesday, April 4, 2006 5:48pm
*+****
*+**** Carolyn--Isaac entered
math111e_Room1. Tuesday, April 4, 2006 5:53pm
*+**** Bill--Beck entered
math111e_Room1. Tuesday, April 4, 2006 5:54pm
Bill Beck>>aHi, Ann, Bridget,
*+**** Lisa--Schloer entered
math111e_Room1. Tuesday, April 4, 2006 5:54pm
Bill Beck>>Hi, Lisa!
Lisa Schloer>>hello
Carolyn Isaac>>hi
*+**** Wendy--Riggin entered
math111e_Room1. Tuesday, April 4, 2006 5:55pm
Bridget Tully>>hi
Wendy Riggin>>Hi everybody
*+**** Bill--Beck entered
math111e_Room1. Tuesday, April 4, 2006 5:57pm
Bill Beck>>Hi, Wendy!
Bill Beck>>The Internet is very slow
tonight!
Bill Beck>>I'm not getting responses from
anybody!
Bill Beck>>I'm going to disconnect and
reconnect.
*-**** Bill--Beck left
math111e_Room1. Tuesday, April 4, 2006 5:58pm
*+**** Jaime--Bankowski
entered math111e_Room1. Tuesday, April 4, 2006 5:58pm
*+**** Bill--Beck entered
math111e_Room1. Tuesday, April 4, 2006 5:59pm
Bill Beck>>Hi, Jaime!
Bill Beck>>Can anybody hear me?
Carolyn Isaac>>yes
Lisa Schloer>>loud and clear
Wendy Riggin>>Yes
Sharon Cochran>>Yes
Jaime Bankowski>>hello
Bill Beck>>Okay, let's get started.
Wendy Riggin>>OK
*+**** Anna--Kocherzhenko
entered math111e_Room1. Tuesday, April 4, 2006 6:00pm
Bill Beck>>Let me know when you are on page
Walk p1, please.
Sharon Cochran>>there
Bill Beck>>Hi, Anna!
Wendy Riggin>>There
Anna Kocherzhenko>>hello
Carolyn Isaac>>there
Lisa Schloer>>there
Ann Willem>>ok
*+**** Casey--Udoff entered
math111e_Room1. Tuesday, April 4, 2006 6:00pm
Bill Beck>>Hi, Casey, we're on page Walk21
p1.
Casey Udoff>>ok, thanks
Bill Beck>>This distribution is measurement
of reaction times.
*+**** Sharon--Merson entered
math111e_Room1. Tuesday, April 4, 2006 6:02pm
Bill Beck>>Drivers were shown a picture of a
boy on a bike and their reactions times in pressing the brake were measured
Bill Beck>>Hi, Sharon M.!
Bill Beck>>We are on page Walk21P1.
Sharon Merson>>Hi
Sharon Merson>>thanks
Bill Beck>>Notice most people responded
within .03 or .04 seconds.
Bill Beck>>Go to page 2, please.
Bill Beck>>Here's the graph of this
frequency distribution.
Bill Beck>>Go to page 3, please.
Bill Beck>>You'll frequently hear that a
distribution is "skewed"
Bill Beck>>It can be skewed right or skewed
left.
*+**** Nicole--Russell
entered math111e_Room1. Tuesday, April 4, 2006 6:04pm
Nicole Russell>>hi
Bill Beck>>That refers to the relationship
between the mean and the median.
Bill Beck>>Hi, Nicole!
Bill Beck>>We are on page Walk21p3
Bill Beck>>Let's go to page 4, please.
Bill Beck>>I won't test you on
"skewed", but it's handy to know this term.
Bill Beck>>Go to page 5, please.
Bill Beck>>Lots of very good grades and
almost as many very poor grades.
Bill Beck>>More As and Fs than Cs
Bill Beck>>Not an uncommon distribution now
days.
Bill Beck>>Go to page 6, please.
Bill Beck>>We're going to focus on
"Normal Distributions" for a couple of weks.
Bill Beck>>weeks
Bill Beck>>In a normal distribution, the
mean, median and mode are the same (or very close to the same).
Nicole Russell>>so does that mean they all
equal each other
Bill Beck>>We also refer to this as a
"bell" shapped curve.
Bill Beck>>Yes, Nicole.
Bill Beck>>Go to page 7, please.
Bill Beck>>xbar is the sample mean.
Bill Beck>>s is the sample standard
deviation.
Bill Beck>>And approximately 68% of the
scores will fall within 1 standard deviation of the mean.
Bill Beck>>For example, suppose xbar = 10
and s = 3
Bill Beck>>10+3 = 13
Bill Beck>>10 - 3 = 7
Bill Beck>>Approximately 68% of the scores
will fall between 7 and 13.
Bill Beck>>Okay?
Casey Udoff>>yes
Ann Willem>>ok
Jaime Bankowski>>yes
Sharon Cochran>>yes
Carolyn Isaac>>okay
Bridget Tully>>ok
Sharon Merson>>ok
Lisa Schloer>>k
Wendy Riggin>>ok
Nicole Russell>>so median and mean = 10
Bill Beck>>And the mode, Nicole.
Bill Beck>>Go to page 8, please.
Nicole Russell>>ok
Bill Beck>>For our distribution,
Anna Kocherzhenko>>ok
Bill Beck>>10+2(3) = 10+ 6
= 16
Bill Beck>>10 - 2(3) =
10-6 = 4
Bill Beck>>So approximately 95% of the
scores will lie between 4 and 16
Bill Beck>>Go to page 9, please.
Bill Beck>>The good news is that you don't
have to memorize these values.
Sharon Cochran>>That is good
Bill Beck>>Let's click on Tools, then Table,
please.
Bill Beck>>The diagram at the lot left shows
a region between 0 and z shaded red.
Bill Beck>>We'll worry about what z
represents later.
Bill Beck>>In the table, for a value of z =
.13, do you see that A = .052?
Sharon Cochran>>yes
Carolyn Isaac>>yes
Casey Udoff>>yes
Anna Kocherzhenko>>yes
Wendy Riggin>>yes
Nicole Russell>>yes
Lisa Schloer>>yea
Ann Willem>>k
Nicole Russell>>so the shaded region = A
Bill Beck>>Yes, Nicole.
*-**** Bill--Beck left
math111e_Room1. Tuesday, April 4, 2006 6:14pm
Bill Beck>>Let's look in the column where z
= 1.00
Bill Beck>>You'll have to scroll down to get
to that point.
Bill Beck>>What value of A is associated
with z = 1.00?
Sharon Merson>>ok
Sharon Merson>>.341
Bill Beck>>RIGHT
Anna Kocherzhenko>>.341
Bill Beck>>right
Bill Beck>>Did we all get .341?
Casey Udoff>>yes
Wendy Riggin>>yes
Sharon Merson>>yup
Nicole Russell>>yes
Sharon Cochran>>yes
Lisa Schloer>>yes
Carolyn Isaac>>yes
Ann Willem>>yes
Jaime Bankowski>>yes
Bill Beck>>Also notice that .341 + .341 =
.682 which is approximately 68%
Bill Beck>>Now let's look for z = 2.00
Ann Willem>>cool
Casey Udoff>>.477
Anna Kocherzhenko>>.477
Bill Beck>>RIGHT
Sharon Cochran>>.477
Bill Beck>>right
Bill Beck>>And notice that .477 + .477 =
.954 which is almost 95%
Bill Beck>>That value of z measures the
number of standard deviations from the mean.
*-**** Jaime--Bankowski left
math111e_Room1. Tuesday, April 4, 2006 6:17pm
Bill Beck>>Okay let's click on "hide
'em" please.
Ann Willem>>does this table have a name
Bill Beck>>It's the area under the curve for
a normal distribution, Ann.
Bill Beck>>Now let's go back to page 8,
please.
Ann Willem>>ok
Bill Beck>>This diagram shows a shaded
region 2 standard deviations to the right of the mean and a shaded region that
is 2 standard deviations to the left of the mean.
Bill Beck>>.477 + .477 = .954 or
approximately 95%.
Bill Beck>>Okay?
Bridget Tully>>k
Ann Willem>>ok
Anna Kocherzhenko>>ok
Sharon Cochran>>ok
Wendy Riggin>> ok
Nicole Russell>>k
Sharon Merson>>ok
Carolyn Isaac>>ok
Lisa Schloer>>ok
Bill Beck>>Okay, let's go to page 9, please.
Bill Beck>>This is 3 standard deviations to
the right of the mean and 3 standard deviations to the left of the mean.
Bill Beck>>Go to page 10, please.
Bill Beck>>We've shaded the region between 0
and z = 1.2 (or 1.2 standard deviations from the mean).
Bill Beck>>Let's click on Tools, the Table,
please and get A for z = 1.2
Nicole Russell>>.385
Bill Beck>>RIGHT
Bill Beck>>Did we all get .385?
Anna Kocherzhenko>>yes
Casey Udoff>>yup
Sharon Merson>>yes
Wendy Riggin>>yes
Carolyn Isaac>>yes
Ann Willem>>.385
Sharon Cochran>>yep
Lisa Schloer>>yes
Ann Willem>>yes
Bill Beck>>Okay, go to page 11, please.
Bill Beck>>Go to page 12, please.
Bill Beck>>This diagram doesn't quite match
our table,
Bill Beck>>But it turns out that the area
under the normal curve is symmetrical, so we can use z = .55 to get the value
between z = 0 and z = -.55
Bill Beck>>Okay?
Sharon Merson>>ok
Casey Udoff>>yes
Sharon Cochran>>ok
Nicole Russell>>ok
Carolyn Isaac>>ok
Bill Beck>>Go to the table and get A,
please.
Sharon Merson>>.209
Ann Willem>>.209
Anna Kocherzhenko>>0209
Casey Udoff>>.209
Bill Beck>>RIGTH
Bill Beck>>RIGHT
Bill Beck>>Go to page 13,please.
Bill Beck>>Good, he agrees with us!
*+**** Jaime--Bankowski
entered math111e_Room1. Tuesday, April 4, 2006 6:24pm
Bill Beck>>Go to page 14,please.
Bill Beck>>Hi again, Jaime. We are on page Walk21p13
Bill Beck>>Go to page 14, please.
Bill Beck>>Go to page 15, please.
Bill Beck>>ALWAYS Sketch a graph!
Bill Beck>>Go to page 16, please.
Bill Beck>>I refer to this a "detached
region."
Bill Beck>>The shaded region doesn't touch
the line for the mean, median, mode, so it is a detatched region.
Bill Beck>>This doesn't look like the
diagram for our table.
Bill Beck>>We'll need an algorithm to solve
problems like this.
Bill Beck>>Go to page 17, please.
Bill Beck>>Go to page 18, please.
Bill Beck>>Go to page 18, please.
Bill Beck>>This looks like the diagram on
our table.
Bill Beck>>Go to page 19, please.
Bill Beck>>This looks like the diagram on
our table.
Bill Beck>>Go to page 20, please.
Bill Beck>>So all we need to do is subtract
to get the area under the detatched region.
Bill Beck>>Make sense?
Casey Udoff>>yes
Anna Kocherzhenko>>yes
Wendy Riggin>>yes
Lisa Schloer>>ok
Bill Beck>>Okay, let's go to page 21,please.
Carolyn Isaac>>yes
Bill Beck>>For z = 1.83, A = .466
Bill Beck>>Go to page 22,please.
Bill Beck>>For z = .50, A = .192
Bill Beck>>Go to page 23,please.
Bill Beck>>A little subtraction.
Ann Willem>>.466 -
.192 = .274
Bill Beck>>RIGHT
Bill Beck>>You should always sketch a graph
of your situation.
Ann Willem>>this acutually makes sense
Bill Beck>>If you have a detatched region,
you'll have to use an algorighm like this one.
Bill Beck>>lol
Bill Beck>>Great!
Bill Beck>>Okay, let's go to the last
walktlhru before we go on spring break.
Bill Beck>>Let me know when you are on page
Walk22 p1, pleae.
Ann Willem>>ok
Lisa Schloer>>there
Wendy Riggin>>ok
Casey Udoff>>there
Carolyn Isaac>>there
Sharon Merson>>there
Jaime Bankowski>>when is this weeks homework
due
Casey Udoff>>when is the hw due?
Sharon Cochran>>No meetin next week?
Bill Beck>>The Tuesday AFTER Spring Break.
Bill Beck>>No meeting next week.
Sharon Cochran>>ok
Casey Udoff>>the 18th?
Carolyn Isaac>>ok
Bill Beck>>Go to page 2,please.
*-**** Ann--Willem left
math111e_Room1. Tuesday, April 4, 2006 6:33pm
*+**** Ann--Willem entered
math111e_Room1. Tuesday, April 4, 2006 6:33pm
Bill Beck>>This time we were given the mean
and the standard deviation. But our
table has z, which indicates "how many standard deviations from the
mean."
Bill Beck>>We need to calculate the z score.
Bill Beck>>Go to page 3,please.
Bill Beck>>Everybody loves a formula!
Bill Beck>>Especially an easy formula.
Sharon Cochran>>Yep!
Bill Beck>>x is our score.
Bill Beck>>xbar is the mean
Bill Beck>>s is the standard deviation.
Bill Beck>>So it's a matter of "plug
and chug."
Bill Beck>>Go to page 4,please.
Bill Beck>>Since we've shaded a region to
the left of the mean, we should have expected a negative value for z.
Bill Beck>>Go to page 5, please.
Bill Beck>>My scale isn't very good, but the
shaded region represents approximately 5.2% of the scores.
Bill Beck>>Okay?
Casey Udoff>>yes
Carolyn Isaac>>ok
Anna Kocherzhenko>>ok
Sharon Cochran>>yes
Sharon Merson>>ok
Lisa Schloer>>ok
Wendy Riggin>>ok
Bill Beck>>Okay, let's go to page 6, please.
Bill Beck>>Our first task is to sketch a
graph!
Bill Beck>>Go to page 7, please.
Bill Beck>>Go to page 8, please.
Bill Beck>>12 is to the right of the mean,
10
Bill Beck>>And we want the scores that are
to the right of 12, so we've shaded the region to the right of 12
Bill Beck>>Go to page 9, please.
Bill Beck>>Since we have a detatched region,
we'll need an algorithm
Bill Beck>>Go to page 10, please.
Bill Beck>>Both of these are regions we
could find in our table.
Bill Beck>>Go to page 11, please.
Bill Beck>>Then we need to subtract.
Bill Beck>>Go to pgae 12,please.
Bill Beck>>We don't need to use our table
for this one. We know the median is the
same as the mean, and we know 50% of the scores are to the right of the median.
Bill Beck>>Okay?
Nicole Russell>>ok
Casey Udoff>>yes
Sharon Cochran>>ok
Carolyn Isaac>>ok
Carolyn Isaac>>
Lisa Schloer>>ok
Wendy Riggin>>ok
Anna Kocherzhenko>>ok
Ann Willem>>ok
Bill Beck>>Go to page 13, please.
Bill Beck>>We need a z score for the other
region, so we'll use our formula.
Bill Beck>>We got z = 1, so A = .341
Bill Beck>>Go to page 14,please.
Bill Beck>>A little subtraction is called
for.
Bill Beck>>Go to page 15,please.
Bill Beck>>Make sense?
Sharon Cochran>>ok
Lisa Schloer>>yes
Anna Kocherzhenko>>yes
Casey Udoff>>yes
Sharon Merson>>ok
Ann Willem>>yes
Nicole Russell>>yes
Carolyn Isaac>>yes
Wendy Riggin>>ok
Bill Beck>>Okay, Class, that's it for
tonight.
Bill Beck>>Any questions?
Casey Udoff>>nope
Sharon Cochran>>HAve a nice break!
Wendy Riggin>>test grades?
Carolyn Isaac>>So no class next week or
homework?
Sharon Merson>>I might have missed it , but
when will test 2 scores be out?
Jaime Bankowski>>whenever I go to get the
chat log i alway get the summers chat logs
Lisa Schloer>>mr beck have you graded the
test
Bill Beck>>I'll be back home on Friday or
Saturday, so I'll pick up your papers and grade them as quickly as possible.
Sharon Merson>>thanks
Casey Udoff>>ok
Ann Willem>>ok
Wendy Riggin>>Thank you
Ann Willem>>good night
Casey Udoff>>night
*-**** Wendy--Riggin left
math111e_Room1. Tuesday, April 4, 2006 6:43pm
*-**** Casey--Udoff left
math111e_Room1. Tuesday, April 4, 2006 6:43pm
Sharon Cochran>>NIght!
Sharon Merson>>Everyone have a great week off!
*-**** Sharon--Cochran left
math111e_Room1. Tuesday, April 4, 2006 6:43pm
Bill Beck>>G"night, Class.
*-**** Nicole--Russell left
math111e_Room1. Tuesday, April 4, 2006 6:44pm
Bill Beck>>See you in 2 weeks!
*-**** Ann--Willem left
math111e_Room1. Tuesday, April 4, 2006 6:44pm
Lisa Schloer>>night
Anna Kocherzhenko>>good night and enjoy
spring break))
*-**** Lisa--Schloer left
math111e_Room1. Tuesday, April 4, 2006 6:44pm
Sharon Merson>>nite
Bill Beck>>G'night!
Jaime Bankowski>>is there a reason why I
always get the summers chat log
*-**** Bridget--Tully left
math111e_Room1. Tuesday, April 4, 2006 6:44pm
*-**** Anna--Kocherzhenko
left math111e_Room1. Tuesday, April 4, 2006 6:44pm
Bill Beck>>I've gotten a little lazy,
Jaime. I'll work on that tonight.
Jaime Bankowski>>thanks
*-****
Bill Beck>>Night
*-**** Bill--Beck left
math111e_Room1. Tuesday, April 4, 2006 6:44pm
Carolyn Isaac>>Good night
*-**** Carolyn--Isaac left
math111e_Room1. Tuesday, April 4, 2006 6:45pm
*+**** Cheryl--Bagley entered
math111e_Room1. Tuesday, April 4, 2006 7:03pm
*-**** Jaime--Bankowski left
math111e_Room1. Tuesday, April 4, 2006 7:04pm
*-**** Cheryl--Bagley left
math111e_Room1. Tuesday, April 4, 2006 7:04pm
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Session in math111e_Room1
ended. (all participants have left).
Tuesday, April 4, 2006 7:04pm
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