Download Statistics Mid-Unit Review

Math 20-2
Statistics
Statistics Mid-Unit Review
1. The following list gives the weight, in pounds, of the members of the Edmonton Eskimos
football team:
165
170
175
183
185
185
185
188
188
189
191
195
195
196
197
205
205
210
210
210
210
215
215
216
225
225
229
230
235
235
240
248
250
255
255
265
270
300
300
300
300
302
310
315
320
335
a) Use your calculator to find the mean, median, mode, standard deviation, and range of the
weights. Round to the nearest tenth. (Don’t forget units!)
b) Complete the frequency table, then make a histogram or frequency polygon of the data.
(Don’t forget to label and scale the axes!)
Weight (lb)
160-175
Frequency
175-190
190-205
c) Put the frequency table into L1 and L2 in your calculator, and then find the mean,
median, and standard deviation again. How do they compare to the answers you got in
part a?
d) Describe how the data is distributed. Does it appear to be a normal distribution? Explain.
Math 20-2
Statistics
2. Twila and Amber keep a log of the amount of time, in minutes, they spend doing homework
each school day for two weeks:
Twila:
Amber:
45
80
55
10
50
65
40
15
55
75
40
30
60
40
45
85
40
20
35
35
a) Find the mean, median, mode, range and standard deviation for each girl’s homework
times. Round to the nearest tenth, if necessary.
b) Who spends more time on homework, on average?
c) Who is more consistent? Explain.
3. Tyson wants to buy a new cell phone. He researched the cell phone he was considering
buying and learned that the lifetime of the phone was normally distributed with a mean of 30
months and a standard deviation of 6 months.
a) Mark the intervals on the normal distribution curve below. (Don’t forget to label the
horizontal axis.)
34%
0.15%
34%
2.35%
2.35%
13.5%
13.5%
0.15%
b) If Tyson purchases this cell phone, what is the likelihood that it will last longer than 3
years?
c) The company will replace cell phones that last less than 18 months. In a shipment of 350
phones, approximately how many will they have to replace?
Math 20-2
Statistics
4. On a recent Math 30-2 diploma exam, 99.7% of students in Alberta got between 35% and
89%. If the marks were normally distributed, find the mean and standard deviation of the
marks.
34%
0.15%
34%
2.35%
2.35%
13.5%
13.5%
0.15%
5. The company payroll of Sweetwater Communications has a mean monthly salary of $5400
with a standard deviation of $800, as represented by the normal curves below.
a) Employees at Clearstream Communication Technologies have a mean monthly salary of
$5400 as well, but a standard deviation of $950. Sketch this normal distribution on the
same axis as Sweetwater’s.
b) The employees at Sweetwater Communications are all going to receive a raise of $150
per month. Sketch the new normal distribution on the axis below.