In: Statistics and Probability
DATA:
Spending by Men Spending by Women
85 90
102 79
139 71
90 119
89 90
52 180
49 88
140 56
90 110
64 82
96 64
132 129
117 28
88 13
92 140
105 62
95 32
119 220
118 72
124 90
131 80
113 56
124 82
71 56
115 88
95 104
102 54
94 108
111 86
85 88
87 38
92 66
92 100
72 57
97 59
83 89
118 95
108 37
104 86
110 62
0 66
0 129
0 119
0 76
0 75
0 101
0 85
0 68
0 67
0 36
0 90
0 99
0 64
0 54
0 86
0 79
0 82
0 65
0 110
0 69
A consumer research firm believe that men and women shop at malls for different reasons, and spend different amounts of money when they shop. While women shop more frequently and for longer amounts of time, men shop less frequently, but tend to spend more each time when they do shop. The research firm has collected spending data for 40 men and 60 women at a local mall and wish to analyze if men spend more when they shop then women based on this data.
NOTE: For this data set, we are assuming UNEQUAL VARIANCES.
a. Specify the competing Null and Alternate hypotheses that you will use to test the economist’s claim.
Null Hypothesis:
Alternative Hypothesis:
b. Is this a one-tailed test or a two-tailed test? Explain why.
Is this test of “independent samples” or “dependent samples”? Explain why.
c. Calculate the value of the t statistic and the appropriate p-value. Provide mean values, and provide the values for the following variables from the output: Mean Spending by Men: Mean Spending by Women: Test Statistic: p-value:
d. At the 99% confidence level (alpha = 0.01), does the data support the researchers claim? Explain how you came to this conclusion.
a)
Ho : µ1 - µ2 = 0
Ha : µ1-µ2 > 0
b)
one-tailed test
independent samples
c)
Level of Significance , α =
0.01
Sample #1 ---->
MEN
mean of sample 1, x̅1= 99.75
standard deviation of sample 1, s1 =
21.35
size of sample 1, n1= 40
Sample #2 ----> WOMEN
mean of sample 2, x̅2= 82.10
standard deviation of sample 2, s2 =
33.87
size of sample 2, n2= 60
difference in sample means = x̅1-x̅2 =
99.7500 - 82.1 =
17.65
std error , SE = Sp*√(1/n1+1/n2) =
5.5243
t-statistic = ((x̅1-x̅2)-µd)/SE = (
17.6500 - 0 ) /
5.52 = 3.195
Degree of freedom, DF= n1+n2-2 =
97
p-value = 0.00094 [excel
function: =T.DIST.RT(t stat,df) ]
d)
Conclusion: p-value <α , Reject null
hypothesis
There is enough evidence that Men average spending is more than
women.
THANKS
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