1. Coco Martinez is the Head of the of the Prow, Vince, Sean & Noe Marketing, a
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Question
1. Coco Martinez is the Head of the of the Prow, Vince, Sean & Noe Marketing, a leading marketing consulting fim which provides marketing and advertising consulting services. Coco is currently facing with four marketing-related problems which must be decided soon, but must be supported with factual evidences. When not given proper decision and interpretation, this would put his consultancy business into a dilemma of labeling "erratic" and "irresolute" by his clients. Help him solve several issues on marketing to win the trust of his clients, using the approprnate test of hypothesis between means. a Celebrity endorsement of products is a common technique. A group of 98 people was shown an ad containing a celebrity endorsement, and a second group of 98 was shown the same ad but using an unknown actor. Each participant rated the commercial's believability on a scale of 0 (not believable) to 10 (very believable) Results were as follows: Believability of Ad Type of Ad Celebrity ad Non-celebrity ad Mean 3.82 3.97 Standard Deviation 2.63 2.51 Is there sufficient evidence to indicate that the use of a celebrity endorsement results in a true mean believability rating that differs from the true mean rating for non- celebrity endorsements? Use a level 0.05 test bl Twenty-four infants paired according to birth weight were used to compare an enriched formula with a standard formula. Weight gains (in grams) are given. PairEnriched Formula Standard Formula 3,604 2,950 3,344 4,022 4,316 3,077 2,988 5,200 4,653 3,218 3,461 2,999 3,140 3,100 2,810 3,761 3,774 2,630 2,988 4,388 5,133 3,621 3,679 3,500 6 10 12 Test Ho: Hd0 against this alternative hypothesis at significance level. 05. Assume populations to be approximately distributed with equal variancesExplanation / Answer
Question 1
Part a
Here, we have to use independent samples t test for difference between population means. The null and alternative hypothesis for this test is given as below:
Null hypothesis: H0: There is no significant difference in the mean believability rating if ad uses the celebrity and ad does not use the celebrity.
Alternative hypothesis: Ha: There is a significant difference in the mean believability rating if ad uses the celebrity and ad does not use the celebrity.
The level of significance or alpha value is given as 0.05.
Results for this test by using excel are summarised in the following table:
[Excel Note: Open Excel > Data > Data Analysis > t-test assuming equal population variances]
[If data is summarised, above excel data analysis tool would not be work. In this case, go to excel settings > get ad on > get PHStat or other ad on, this will give results for summarised data.]
[Excel data analysis tools are only used for un-summarised data.]
Pooled-Variance t Test for the Difference Between Two Means
(assumes equal population variances)
Data
Hypothesized Difference
0
Level of Significance
0.05
Population 1 Sample
Sample Size
98
Sample Mean
3.82
Sample Standard Deviation
2.63
Population 2 Sample
Sample Size
98
Sample Mean
3.97
Sample Standard Deviation
2.51
Intermediate Calculations
Population 1 Sample Degrees of Freedom
97
Population 2 Sample Degrees of Freedom
97
Total Degrees of Freedom
194
Pooled Variance
6.6085
Standard Error
0.3672
Difference in Sample Means
-0.1500
t Test Statistic
-0.4084
Two-Tail Test
Lower Critical Value
-1.9723
Upper Critical Value
1.9723
p-Value
0.6834
Do not reject the null hypothesis
We do not reject the null hypothesis that there is no significant difference in the mean believability rating if ad uses the celebrity and ad does not use the celebrity.
There is insufficient evidence to conclude that there is a significant difference in the mean believability rating if ad uses the celebrity and ad does not use the celebrity.
Part b
Here, we have to use paired t test for checking the given claim. The null and alternative hypotheses for this test are given as below:
Null hypothesis: H0: Average weight gain in grams with a enriched formula is same as average weight gain in grams with a standard formula. There is no any significant difference in average weight gains with an enriched formula and standard formula.
Alternative hypothesis: Ha: Average weight gain in grams with an enriched formula is not same as average weight gain in grams with a standard formula. There is a significant difference in average weight gains with an enriched formula and standard formula.
H0: µd = 0 vs. Ha: µd ? 0 (Two tailed test)
? = 0.05
Excel output for this test is given as below:
Enriched formula
Standard formula
Di
(Di - DBar)^2
3604
3140
464
126025
2950
3100
-150
67081
3344
2810
534
180625
4022
3761
261
23104
4316
3774
542
187489
3077
2630
447
114244
2988
2988
0
11881
5200
4388
812
494209
4653
5133
-480
346921
3218
3621
-403
262144
3461
3679
-218
106929
2999
3500
-501
372100
Dbar =
109
t-Test: Paired Two Sample for Means
Enriched formula
Standard formula
Mean
3652.666667
3543.666667
Variance
544439.5152
491543.1515
Observations
12
12
Pearson Correlation
0.799850744
Hypothesized Mean Difference
0
df
11
t Stat
0.827056012
P(T<=t) one-tail
0.212891446
t Critical one-tail
1.795884814
P(T<=t) two-tail
0.425782891
t Critical two-tail
2.200985159
Paired t Test
Data
Hypothesized Mean Difference
0
Level of significance
0.05
Intermediate Calculations
Sample Size
12
DBar
109.0000
Degrees of Freedom
11
SD
456.5435
Standard Error
131.7928
t Test Statistic
0.8271
Two-Tail Test
Lower Critical Value
-2.2010
Upper Critical Value
2.2010
p-Value
0.4258
Do not reject the null hypothesis
We do not reject the null hypothesis that Average weight gain in grams with a enriched formula is same as average weight gain in grams with a standard formula. There is no any significant difference in average weight gains with an enriched formula and standard formula.
Pooled-Variance t Test for the Difference Between Two Means
(assumes equal population variances)
Data
Hypothesized Difference
0
Level of Significance
0.05
Population 1 Sample
Sample Size
98
Sample Mean
3.82
Sample Standard Deviation
2.63
Population 2 Sample
Sample Size
98
Sample Mean
3.97
Sample Standard Deviation
2.51
Intermediate Calculations
Population 1 Sample Degrees of Freedom
97
Population 2 Sample Degrees of Freedom
97
Total Degrees of Freedom
194
Pooled Variance
6.6085
Standard Error
0.3672
Difference in Sample Means
-0.1500
t Test Statistic
-0.4084
Two-Tail Test
Lower Critical Value
-1.9723
Upper Critical Value
1.9723
p-Value
0.6834
Do not reject the null hypothesis
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