In: Statistics and Probability
30 pts.
4. Management of a major company has made the following assumptions regarding their consumer profile.
The company hired market researchers to determine the validity of their consumers’ demographic assumptions. The researchers conducted survey and focus groups to evaluate the purchasing pattern of the company’s current consumers. In a survey of 800 consumers, 510 respondents were women and 300 indicated they primarily collect information on the company’s products online. The average age of the respondents was 43 years with standard deviation of 8 years and the average reported annual expenditure was $48 with standard deviation of $10.5
Determine which of the management’s demographic assumption is supported by the data. Use 0.05 level of significance. Provide conclusion in non-technical language.
Ho : p = 0.6
H1 : p > 0.6
(Right tail test)
Level of Significance, α =
0.05
Number of Items of Interest, x =
510
Sample Size, n = 800
Sample Proportion , p̂ = x/n =
0.6375
Standard Error , SE = √( p(1-p)/n ) =
0.0173
Z Test Statistic = ( p̂-p)/SE = ( 0.6375
- 0.6 ) / 0.0173
= 2.1651
p-Value = 0.0152 [Excel
function =NORMSDIST(-z)
Decision: p-value<α , reject null
hypothesis
----------------------------------------------------------------------------------------------------------------
Less than 40% of our customer get information on our products through online resources
Ho : p = 0.4
H1 : p < 0.4
(Left tail test)
Level of Significance, α =
0.05
Number of Items of Interest, x =
300
Sample Size, n = 800
Sample Proportion , p̂ = x/n =
0.3750
Standard Error , SE = √( p(1-p)/n ) =
0.0173
Z Test Statistic = ( p̂-p)/SE = ( 0.3750
- 0.4 ) / 0.0173
= -1.4434
critical z value =
-1.645 [excel function =NORMSINV(α)]
p-Value = 0.0745 [excel
function =NORMSDIST(z)]
Decision: p value>α ,do not reject null hypothesis
----------------------------------------------------------------------------------------------
The average age of a purchasers is below 45 years.
Ho : µ = 45
Ha : µ < 45
(Left tail test)
Level of Significance , α =
0.05
sample std dev , s = 8.0000
Sample Size , n = 800
Sample Mean, x̅ = 43.0000
degree of freedom= DF=n-1= 799
Standard Error , SE = s/√n = 8.0000 / √
800 = 0.2828
t-test statistic= (x̅ - µ )/SE = ( 43.000
- 45 ) / 0.2828
= -7.07
p-Value = 0.0000 [Excel formula
=t.dist(t-stat,df) ]
Decision: p-value<α, Reject null hypothesis
---------------------------------------------------------------------------------------------------
Ho : µ = 45
Ha : µ > 45
(Right tail test)
Level of Significance , α =
0.05
sample std dev , s = 10.5000
Sample Size , n = 800
Sample Mean, x̅ = 48.0000
degree of freedom= DF=n-1= 799
Standard Error , SE = s/√n = 10.5000 / √
800 = 0.3712
t-test statistic= (x̅ - µ )/SE = ( 48.000
- 45 ) / 0.3712
= 8.08
p-Value = 0.0000 [Excel formula
=t.dist(t-stat,df) ]
Decision: p-value<α, Reject null hypothesis
There is sufficient evidence that Over 60% of all shoppers are women.
There is not sufficient evidence that Less than 40% of our customer get information on our products through online resources
There is sufficient evidence that The average age of a purchasers is below 45 years.
There is sufficient evidence thatThe average annual expenditure by the shoppers exceed $45.
Please revert back in case of any doubt.
Please upvote. Thanks in advance.