question 1

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

In a survey of 1880 adults from countryA, 508 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.)

The point estimate forq,

q, is

(Round to three decimal places asneeded.)

question 2

If all other quantities remain thesame, how does the indicated change affect the minimum sample sizerequirement?

(a) Increase in the level of confidence

(b) Increase in the error tolerance

(c) Increase in the population standard deviation

(a) How does an increase in the level of confidence affect the minimum sample sizerequirement? Choose the correct answer below.

An increase in the level of confidence _______

the minimum sample size required.

(b) How does an increase in the error tolerance affect the minimum sample sizerequirement? Choose the correct answer below.

An increase in the error tolerance _______

the minimum sample size required.

(c) How does an increase in the population standard deviation affect the minimum sample sizerequirement? Choose the correct answer below.

An increase in the population standard deviation ______ the minimum sample size required

question 4

A researcher wishes toestimate, with 90% confidence, the population proportion of adults who think the president of their country can control the price of gasoline. Her estimate must be accurate within 1% of the true proportion.

a) No preliminary estimate is available. Find the minimum sample size needed.

b) Find the minimum sample sizeneeded, using a prior study that found that 42% of the respondents said they think their president can control the price of gasoline.

c) Compare the results from parts(a) and(b).

(a) What is the minimum sample size needed assuming that no prior information isavailable?

n=

(Round up to the nearest whole number asneeded.)

(b) What is the minimum sample size needed using a prior study that found that 42% of the respondents said they think their president can control the price ofgasoline?

n=

(Round up to the nearest whole number asneeded.)

(c) How do the results from (a) and (b)compare?

A.

Having an estimate of the population proportion has no effect on the minimum sample size needed.

B.

Having an estimate of the population proportion raises the minimum sample size needed.

C.

Having an estimate of the population proportion reduces the minimum sample size needed.

question 5

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.

100,145

80,972

78,306

68,184

51,404

67,969

94,597

65,695

79,112

73,343

44,624

86,949

61,111

57,719

55,281

77,731

47,974

98,925

81,207

93,379

63,461

75,090

50,934

60,760

92,344

84,522

79,449

64,014

74,475

57,247

46,561

90,158

75,568

62,190

83,163

(a) Find the sample mean.

x=

(Type an integer or decimal rounded to two decimal places asneeded.)

(b) Find the sample standard deviation.

s=

(Type an integer or decimal rounded to two decimal places asneeded.)

(c) Construct a98% confidence interval for the population mean. ___ << ___

(Round to the nearest integer asneeded.)

question 6

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

(0.178,0.300)

The margin of error is

The sample mean is