Download AP Statistics The Standard Normal Curve

AP Statistics The Standard Normal Curve #2
Name______________________
Show all work for these problems on a separate sheet.
1. For the following data create a Normal Probability Plot. Make a sketch of the plot,
stating the window your calculator created using Zoom 9. Does the data appear to be
normally distributed? EXPLAIN your answer.
Scores on a Math Test in BC Calculus:
89, 68, 77, 82, 76, 74, 59, 74, 79, 66, 84, 75, 72, 76, 78, 78, 95, 93, 90
2. For the data in #1, find the mean and standard deviation using a calculator. Write down
the break points for ±1 ±2 and ±3 . Place the data in order and count the number of
items in each of the classes. Then, find the percent of the data in each standard deviation
class. Write them out on your sheet. Does this data support the idea that the data is
normally distributed? Explain.
3. Use the data from #1. Make a histogram (Sketch the graph). Also, make a modified box
and whisker plot for the data. Are there any outliers? Do you think this has an effect on
the data? Which method of assessing normality would you use first if you were testing
data, the graph or the Normal Probability Plot? What makes you choose this?
4. Kameron got a 715 on the SATV. Suppose the mean for this is 520 with a standard
deviation of 75. What would Vincent’s percentile score be? What score would Kameron
need to get on the SATV to have a percentile of 80?
5. For the following data create a Normal Probability Plot. Make a sketch of the plot,
stating the window your calculator created using Zoom 9. Does the data appear to be
normally distributed? EXPLAIN your answer.
6. Cholesterol levels in 25 randomly chosen adults:
188, 210, 176, 189, 173, 215, 185, 168, 219, 186, 210, 300,
180, 214, 250, 172, 180, 218, 170, 189, 215, 190, 275
7. Assume the data for cholesterol in problem #5 is normal. What cholesterol level would
be labeled “High” if the cut off is the 98th percentile? What is the cut-off for dangerous
if it is at the 99th percentile?
8. A traffic study on I-480 outside of Garfield Hts. showed that the average speed of
vehicles on the weekend was normally distributed with a mean speed of 63 mph and a
standard deviation of 5.2 mph. What proportion of the drivers is above the speed of 65
mph? 75 mph? The next weekend patrolmen were told to ticket anyone whose speed
was in the top 5% of the curve. What speed was used as the cut-off?
9. A possible distribution curve is given by the following: a line from (0,0) to (4, 0.5).
Verify if this is a density curve. If it is, find the proportion of the data between .25 and.5,
If not, explain why this part of the question makes no sense