Math 54 Practice 7.3, 8.1 and 8.2
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Math 54
Practice 7.3, 8.1 and 8.2
1. What are the values of 
and 
for the sampling distribution of the sample mean shown?
2. Assume that the heights of men are normally distributed with a mean of 69.8 inches and a standard deviation of 2.8 inches. If 64 men are randomly selected, find the probability that they have a mean height greater than 70.8 inches.
3. Assume that blood pressure readings are normally distributed with a mean of 117 and a standard deviation of 9.6. If 144 people are randomly selected, find the probability that their mean blood pressure will be less than 119.
4. The standard error of the mean is given by__________.
5. The amount of time it takes a student to walk from her home to class has a skewed right distribution with a mean of 14 minutes and a standard deviation of 1 minutes. If data
were collected from 40 randomly selected walks, describe the sampling distribution of x, the sample mean time.
6. A farmer was interested in determining how many grasshoppers were in his field. He knows that the distribution of grasshoppers may not be normally distributed in his field due to growing conditions. As he drives his tractor down each row he counts how many grasshoppers he sees flying away. After several rows he figures the mean number of flights to be 57 with a standard deviation of 12. What is the probability of the farmer will count 60 or more flights on average in the next 40 rows down which he drives his tractor?
7. Describe the sampling distribution of 
. 
= 20,000 
= 600, 
= 0.3
8. A normal probability plot is a graph that plots _____________ versus _____________.
9. The following data represent a random sample of the number of shares of a pharmaceutical company's stock traded for 20 days in 2000.
|
4.28 |
9.2 |
10.7 |
7.82 |
14.14 |
|
5.59
|
9.99
|
9.24
|
12.4
|
13.55 |
|
4.54
|
8.84
|
11.89
|
7.05
|
27.84 |
|
8.01 |
10.44 |
4.58 |
7.54 |
11.18 |
2022-05-21