question 16

Construct the indicated confidence interval for the population mean using thet-distribution. Assume the population is normally distributed.

c=0.95, x=13.3, s=4.0, n=9

The 95% confidence interval using at-distribution is (____,___)

(Round to one decimal place asneeded.)

question 17

In a random sample of 26 people, the mean commute time to work was 30.1 minutes and the standard deviation was 7.2 minutes. Assume the population is normally distributed and use at-distribution to construct a 95% confidence interval for the population mean . What is the margin of error of ? Interpret the results.

The confidence interval for the population mean is (___,____)

(Round to one decimal place asneeded.)

question 18

In a random sample of 13 microwaveovens, the mean repair cost was $85.00 and the standard deviation was $15.30. Using the standard normal distribution with the appropriate calculations for a standard deviation that isknown, assume the population is normallydistributed, find the margin of error and construct a 98% confidence interval for the population mean . A 98% confidence interval using thet-distribution was (73.6,96.4). Compare the results.

The margin of error of is _____

(Round to two decimal places asneeded.)

question 20

The annual earnings(in dollars) of 35 randomly selected microbiologists are shown in the data table. Use the data to(a) find the samplemean, (b) find the sample standarddeviation, and(c) construct a98% confidence interval for the population mean.

100,680

80,565

77,321

67,677

51,352

68,161

93,435

66,262

79,489

73,824

44,689

86,205

61,120

57,654

55,010

77,809

47,441

98,389

81,028

92,972

63,294

74,086

50,886

60,981

92,606

84,518

80,062

64,395

73,548

56,707

46,746

88,880

75,715

61,679

82,967

question 21

Let p be the population proportion for the following condition. Find the point estimates for p and q.

In a survey of 1361 adults from countryA, 311 said that they were not confident that the food they eat in country A is safe.

The point estimate forp,

p, is ____

(Round to three decimal places asneeded.)

question 22

Use the given confidence interval to find the margin of error and the sample proportion.

(0.754,0.780)

E=

(Type an integer or adecimal.)