Question

A researcher selected sample of customs from 4 companies and asked them if the companies care give warranty on sold items or not. Assume observed values from your own (fill the below table by assuming any values of your choice) and test the claim that the proportion of customers of each company who got warranty is the same for each company by choosing alpha of your own choice

	Company A	Company B	Company C	Company D	Total
Warranty: Yes	10	22	36	19	87
Warranty: No	40	55	40	15	150
Total	50	77	76	34	237

Answer 1

The hypothesis being tested is:

H0: The proportion of customers of each company who got a warranty is the same for each company

Ha: The proportion of customers of each company who got a warranty is not the same for each company

observed	expected	O - E	(O - E)² / E
10	21.750	-11.750	6.348
22	21.750	0.250	0.003
36	21.750	14.250	9.336
19	21.750	-2.750	0.348
87	87.000	0.000	16.034
16.03	chi-square
3	df
.0011	p-value

The test statistic is 16.03.

The p-value is 0.0011.

Since the p-value (0.0011) is less than the significance level (0.05), we can reject the null hypothesis.

Therefore, we can conclude that the proportion of customers of each company who got a warranty is not the same for each company.