9. In a study it was found that the averge age of cable TV shoppers
was 55 years. Suppose you want to test the null hypothesis, H 0 :µ = 55,
using a sample of n = 60 cable TV shoppers.
10. A sample of seven mesurements, randomly selected from a
normally distributed population, resulted in the summary statistics =
4.6 and s = 1.2. Complete parts athrough c.
11. A study analysis recent incidents involving terrorist attacks. Data
on the number of individual suicide bombings that occurred in each of
20 sampled terrorist group attcks against a country is reproduced in
the data table below. An Excel/DDXL printout is shown to the right.
Complete parts a through e.
12. When planning for a new forest road to be used for tree
harvesting, planners must select the location to minimize tractor
skidding distance. The skidding distances (in meters) were measured
at 20 randomly selected road sites. The data are given below. A
logger working on the road claims the mean skiddin g distance is
atleast 424 meters. Is there sufficient evidence to refute this claim?
Use α = 0.10 / α = 0.01.
13. For the binomial sample sizes and null hypothesized values of p
in each part, determine whether the sample size is large enough to
meet the required conditions for using the normal approximation to
conduct a valid large-sample hypothesis test of the null hypothesis H 0 :
p = p 0 . Complete parts a through e.
14. Suppose a consumer group rated 49 brands of toothpaste based on
whether or not the brand carries an American Dental Association
(ADA) seal verifying effective decay prevention. The results of a
hypothesis test for the proportion of brands with the seal are shown to
the right. Complete parts a through c.
15. In order to compare the means of two populations, independent
random samples of 410 observations are selected from each
population, with the results found in the table to the right. Complete
parts a through e.