Skilled2020-10-29Added 96 answers
All necessary assumptions are met:
The sampling method for each population is simple random sampling.
Each sample includes at least 10 successes and 10 failures.
Proportion of customers purchasing tractors with warranties
Proportion of customers purchasing tractors without warranties
Difference in proportions
Pooled sample proportion
The standard error (SE) of the sampling distribution difference between two proportions.
where p is the pooled sample proportion,
z value for
Margin of error
Alternate : Ha: Offering the warranty increases the proportion of customers who eventually purchase a tractor.
Calculating Test statistic z :
Decision about the null hypothesis
At 0.05 significance level
Since it is observed that
Using the P-value approach: The p-value is
Offering the warranty increases the proportion of customers who eventually purchase a tractor.
Yes, they should offer a guarantee