Question 8 (1 point)

Question 8 options:

The number of cell phones per 100 residents in countries in Europe is given in Table #1 for the year 2010.The number of cell phones per 100 residents in countries of the Americas is given in Table #2 also for the year 2010 ("Population reference bureau," 2013).

Table #1: Number of Cell Phones per 100 Residents in Europe

100

76

100

130

75

84

112

84

138

133

118

134

126

188

129

93

64

128

124

122

109

121

127

152

96

63

99

95

151

147

123

95

67

67

118

125

110

115

140

115

141

77

98

102

102

112

118

118

54

23

121

126

47

Table #2: Number of Cell Phones per 100 Residents in the Americas

158

117

106

159

53

50

78

66

88

92

42

3

150

72

86

113

50

58

70

109

37

32

85

101

75

69

55

115

95

73

86

157

100

119

81

113

87

105

96

Let ₁= mean number of cell phones per 100 residents in countries of Europe.Let ₂ = mean number of cell phones per 100 residents in countries of the Americas.Find the 98% confidence interval for the difference in mean number of cell phones per 100 residents in Europe and the Americas.

(i)Forthesamplefrompopulationwithmean=1:Determinesamplemeanx1andsamplestandarddeviations1

Enter sample mean in decimal form to nearest ten-thousandth, then comma, then sample standard deviation in decimal form to nearest ten-thousandth.Examples of correctly entered answers:

13.2027,2.3471

0.2700,0.0006

-10.3150,0.0790

(ii)Forthesamplefromthepopulationwithmean=2:Determinesamplemeanx2andsamplestandarddeviations2

Enter sample mean in decimal form to nearest ten-thousandth, then comma, then sample standard deviation in decimal form to nearest ten-thousandth.Examples of correctly entered answers:

13.2027,2.3471

0.2700,0.0006

-10.3150,0.0790

(iii)Enter the level of significance used for this interval estimate:

Enter in decimal form.Examples of correctly entered answers:0.010.020.050.10

(iv)Determine degrees of freedom df :

Enter value rounded DOWN to nearest integer.

(v)Determine t - score associated with critical value:t_c

Enter in decimal form to nearest thousandth.Examples of correctly entered answers:

0.00110.0200.5000.3712.000

(vi)Determine "error bound of the mean"E

Enter value in decimal form rounded to nearest thousandth.Examples of correctly entered answers:

2.0143.07016.000110.019

(vii) Determine confidence interval estimate of the difference ₁ - ₂ :

Enter lower bound value to nearest ten-thousandth, followed by < , followed by "1-2" for difference, followed by <, followed by upper bound value to nearest ten-thousandth.No spaces between any characters. Do not use italics, but if mathematically necessary use negative signs.Examples of correctly entered answers:

0.0077<1-2<0.0780

13.1012<1-2<18.3941

-9.7300<1-2<-3.0008

(viii)Using the confidence interval, select the most correct description of the result of the survey:

A.We estimate with 98% confidence that the sample mean number of cell phones per 100 residents in countries of Europe is anywhere from 4.3641 to 37.5276 more than the mean number of cell phones per 100 residents in countries of the Americas.

B.We estimate with 98% confidence that the true mean number of cell phones per 100 residents in countries of Europe is anywhere from 4.3641 to 37.5276 more than the mean number of cell phones per 100 residents in countries of the Americas.

C.We estimate with 98% confidence that the true proportion of cell phones per 100 residents in countries of Europe is anywhere from 4.3641 to 37.5276 more than the mean number of cell phones per 100 residents in countries of the Americas.

D.We estimate with 98% confidence that the mean number of cell phones per 100 residents in countries of Europe is anywhere from 4.3641 to 37.5276 less than the mean number of cell phones per 100 residents in countries of the Americas.

Enter letter corresponding to most correct answer