Question 460412: Identical question as one posted but different numbers to calculate. Please look!\Can people really identify their favorite brand of cola? Volunteers tasted Coca-Cola Classic, Pepsi, Diet Coke, and Diet Pepsi, with the results shown below. Research question: At α = .05, is the correctness of the prediction different for the two types of cola drinkers? Could respondents identify their favorite brand in this kind of test? Since it is a 2 × 2 table, try also a two-tailed two-sample z test for π1 = π2 (see Chapter 10 – test of two proportions) and test whether your results are the same as using the Chi-square test for independence. Which test is preferable? Why?
You need to run or to calculate both a Chi-square test of independence and a test of two sample proportions. The p values will be nearly identical if you run both test correctly. The sample size is 368, with 152 for the regular cola drinkers and 216 for the diet cola drinkers. Can Cola Drinkers Tell The Difference?
Correct? Regular Cola Diet Cola Row Total
Yes 56 56 112
No 96 160 256
Col Total 152 216 368
My answer...
Answer:
Ho: cola type and guessing results are the same
Ha: Results are not the same
Ran a 2X2 Chi-Square with the following results:
Test statistic = 5.02
P-Value = .0250
The p- value is greater than 5%, fail to reject the Ho and the results for both colas are the same.
Chi-square Contingency Table Test for Independence
Col 1 Col 2 Total
Row 1 56 56 112
Row 2 96 160 256
Total 152 216 368
5.02 chi-square
1 df
.0250 p-value
Two sample z-test: (can't get this one!) Please advise...and thank you!
Ho: u1=u2
Ha: u1 is unequal to u2
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! Research question: At α = .05, is the correctness of the prediction different for the two types of cola drinkers?
--------------------------------------
Could respondents identify their favorite brand in this kind of test? Since it is a 2 × 2 table, try also a two-tailed two-sample z test for π1 = π2 (see Chapter 10 – test of two proportions) and test whether your results are the same as using the Chi-square test for independence. Which test is preferable? Why?
You need to run or to calculate both a Chi-square test of independence and a test of two sample proportions. The p values will be nearly identical if you run both tests correctly.
-------------------------------------
The sample size is 368, with 152 for the regular cola drinkers and 216 for the diet cola drinkers. Can Cola Drinkers Tell The Difference?
Correct? Regular Cola Diet Cola Row Total
Yes 56 56 112
No 96 160 256
Col Total 152 216 368
============================================
My answer...
Answer:
Ho: Row and column factors are independent
Ha: They are not independent
---------------
Ran a 2X2 Chi-Square with the following results:
Test statistic = 5.02
P-Value = .0250
The p-value is LESS than 5%, so REJECT Ho ;
row and column factors are not independent.
Chi-square Contingency Table Test for Independence
Col 1 Col 2 Total
Row 1 56 56 112
Row 2 96 160 256
Total 152 216 368
5.02 chi-square
1 df
.0250 p-value
Two sample z-test: (can't get this one!) Please advise...and thank you!
Ho: u1=u2
Ha: u1 is not equal to u2
---
I ran a 2-Proportion Ztest and got the following results
P1hat = 56/152
p2hat = 56/216
---
test stat: z = 2.2409
p-value: 0.0250
---
Since the p-value is Less then 5%, reject Ho:
The test results do not support equality of the means.
===========
Cheers,
Stan H.
|
|
|
