Question

Making Decisions with Confidence Intervals

Assume you work for Kimberly Clark Corporation, the makers of Kleenex. The job you are presently working on requires you to decide how many Kleenexes are to be put in the new automobile glove compartment boxes. Complete the following:

1. When do people usually need Kleenexes?

2. What type of data collection technique would you use?

3. Assume you found out that, from your sample of 81 people, on average about 57 Kleenexes are used throughout the duration of a cold, with a sample standard deviation of 15. Construct a 95% confidence interval based on the data.

4. Write a brief summary interpreting your answer in part (3).

5. Explain how you will decide how many Kleenexes will go in the boxes.

Answer 1

1. Kleenex is used as a tissue paper contains special oils or lotions to help keep your skin from getting too dry or cracked from sneezing or rubbing too much. in terms of automobile glove compartment boxes this is a helpful service for hygiene.

2. To collect sample, we will see who all uses Kleenex or are the potential users of Kleenex and take their observations ( number of Kleenex used through out the season ) as a sample value.

3. sample size, n = 81

mean, x_bar = 57

standard deviation, sd = 15

95% confidence interval = x_bar +/- sd*z_critical/sqrt(n)

z_critical at 95% confidence interval = 1.96

x_bar +/- sd*z_critical = 57 +/- 15*1.96/sqrt(81) = 57 +/- 3.267 = ( 53.73, 60.267 )

4. interpretation : we are 95% confident that a person from population will require between 53 to 60 Kleenex during the whole winter season.

5. We will put 57 Kleenex in the box, since, it is the mean of the Kleenex required, based on the previous analysis