Question

A pet store wants to compare day versus evening visiting times to determine when is a more popular time for their Siamese cat exhibit. They randomly observed people viewing the exhibit and noted 30 visitors stayed for an average of 15 minutes with a standard deviation of 3.1 during the day. During the evening, 26 visitors stayed for an average of 9 minutes with a standard deviation of 2.0. Assuming a normal distribution, determine if there is a significant difference in viewing time between day and evening hours.

1. Which test will you use to determine significance?

2. State the null and alternative hypotheses

3. State your research criteria

4.  Calculate your test statistic

5.  State your decision regarding the significance and interpret your results.

6.  Calculate the confidence interval, if applicable.

7.  Calculate the effect size and proportion of variance, if applicable.

Answer 1

1. Two sample t test

2.

3. Parent population is normally distributed with equal variance

4. Test statistic

where

s= 2.6482

t= 8.46

5. degrees of freedom = 30+26-2 =54

P value is less than 0.0001

the result is significant as p value is very less.

Reject the null hypothesis

There is sufficient evidence to conclude that there is significant difference in viewing time between day and evening hours.

6. The 95% confidence interval for difference of means

for 95%, with df =54 ,

Therefore 95% CI

=

= (4.58, 7.42)

7.

= 6/2.6482 = 2.27