Compute the value of the test statistic for the indicated test, based on the information given.

a. Testing H0:=342 vs. Ha:<342, = 11.2, n = 40, x-=339, s = 10.3

b. Testing H0:=105 vs. Ha:>105, = 5.3, n = 80, x-=107, s = 5.1

c. Testing H0:=-13.5 vs. Ha:-13.5, unknown, n = 32, x-=-13.8, s = 1.5

d. Testing H0:=28 vs. Ha:28, unknown, n = 68, x-=27.8, s = 1.3

2. Perform the indicated test of hypotheses, based on the information given.

a. Test H0:=105 vs. Ha:>105 @ a=0.05, unknown, n = 30, x-=108, s = 7.2

b. Test H0:=21.6 vs. Ha:<21.6 @ a=0.01, unknown, n = 78, x-=20.5, s = 3.9

c. Test H0:=-375 vs. Ha:-375 @ a=0.01, = 18.5, n = 31, x-=-388, s = 18.0

3. The government of an impoverished country reports the mean age at death among those who have survived to adulthood as 66.2 years. A relief agency examines 30 randomly selected deaths and obtains a mean of 62.3 years with standard deviation 8.1 years. Test whether the agency's data support the alternative hypothesis, at the 1% level of significance, that the population mean is less than 66.2.

4. The mean increase in word family vocabulary among students in a one-year foreign language course is 576 word families. In order to estimate the effect of a new type of class scheduling, an instructor monitors the progress of 60 students; the sample mean increase in word family vocabulary of these students is 542 word families with sample standard deviation 18 word families.

a. Test at the 5% level of significance whether the mean increase with the new class scheduling is different from 576 word families, using the critical value approach.

b. Compute the observed significance of the test.

c. Perform the test at the 5% level of significance using the p-value approach. You need not repeat the first three steps, already done in part (a).

5. An economist wishes to determine whether people are driving less than in the past. In one region of the country the number of miles driven per household per year in the past was 18.59 thousand miles. A sample of 15 households produced a sample mean of 16.23 thousand miles for the last year, with sample standard deviation 4.06 thousand miles. Assuming a normal distribution of household driving distances per year, perform the relevant test at the 5% level of significance.

6. Two years ago 72% of household in a certain county regularly participated in recycling household waste. The county government wishes to investigate whether that proportion has increased after an intensive campaign promoting recycling. In a survey of 900 households, 674 regularly participate in recycling. Perform the relevant test at the 10% level of significance.