Reference no: EM1318362
1. A random sample of 121 bottles of cologne showed an average content of 4 ounces. It is known that the standard deviation of the contents (i.e., of the population) is 0.22 ounces. The point estimate of the mean content of the bottles is:
a. 0.22
b. 4
c. 121
d. 0.02
2. There are 6 children in a family. The number of children defines a population. The number of simple random samples of size 2 (without replacement) that are possible equals:
a. 12
b. 15
c. 3
d. 16
3. A random sample of 81 automobiles traveling on an interstate showed an average speed of 60 mph and a standard deviation of 13.5 mph. Assume the distribution of speeds of all the cars is normal.
A. Refer to Exhibit 8-2. If we are interested in determining an interval estimate for m at 86.9% confidence, the Z value to use is
a. 1.96
b. 1.31
c. 1.51
d. 2.00
B. Refer to Exhibit 8-2. The standard error of the mean is
a. 13.5
b. 9
c. 2.26
d. 1.5
4. The manager of a grocery store has taken a random sample of 100 customers. The average length of time it took the customers in the sample to check out was 3.1 minutes with a standard deviation of 0.5 minutes. We want to test to determine whether or not the mean waiting time of all customers is significantly more than 3 minutes.
A. Refer to Exhibit 9-4. The standardized test statistic is
a. 1.96
b. 1.64
c. 2.00
d. 0.056
B. Refer to Exhibit 9-4. The p-value is
a. 0.025
b. 0.0456
c. 0.05
d. 0.0228
5. Which of the following statements is not a required assumption for developing an interval estimate of the difference between two sample means when the samples are small?
a. Both populations have normal distributions.
b. s1 = s2 = 1
c. Independent random samples are selected from the two populations.
d. The variances of the two populations are equal.