The number of successes and the sample size are given for a simple random sample from a population. Use the one-proportion z-interval procedure to find the required confidence interval.

13) n = 193, x = 108; 95% level

The number of successes and the sample size are given for a simple random sample from a population. Determine the sample proportion, p.

14) x = 3, n = 16

Use the one-proportion z-test to perform the required hypothesis test. Use the critical-value approach. 15) In a sample of 157 children selected randomly from one town, it is found that 38 of them suffer from asthma. At the 0.05 significance level, do the data provide sufficient evidence to conclude the proportion of all children in the town who suffer from asthma is different from 11%?

The numbers of successes and the sample sizes are given for independent simple random samples from two populations. Use the two-proportions z-interval procedure to obtain the specified confidence interval.

16) x1 = 11, n1 = 43 , x2 = 23, n2 = 55; 90% confidence interval

Use the Wilcoxon signed-rank test to perform the required hypothesis test. Be sure to state the hypotheses and the significance level, to obtain the critical value(s), to compute the value of the test statistic, and to state your conclusion.

17) In 1995, the median age of the residents of one city was 36 years. A random sample taken this year of 10 residents of the town yielded the following ages in years. 5 28 37 49 30 68 11 58 40 34 At the 5% significance level, do the data provide sufficient evidence to conclude that the median age of the residents this year is different from the 1995 median age of 36 years?

Obtain the required point estimate of the mean or predicted y-value. You may presume that the assumptions for regression inferences are met and that x is useful as a predictor of y.

18. Applicants for a particular job, which involves extensive travel in Spanish speaking countries, must take a proficiency test in Spanish. The sample data below were obtained in a study of the relationship between the numbers of years applicants have studied Spanish (x) and their score on the test (y).

x 3 4 4 2 5 3 4 5 3 2

y 57 78 72 58 89 63 73 84 75 48 y = 31.55 + 10.90x

Obtain an estimate of the mean score for all applicants who have studied Spanish for 2.3 years. Round your answer to two decimal places.