Chapter 7, Problem 7.1.1RE

To determine

To construct: The 90% confidence interval for the true mean number of isotopes for all elements with isotopes.

Answer to Problem 7.1.1RE

The 90% confidence interval for the true mean number of isotopes for all elements with isotopes is $\underset{\_}{14.01<\mu <25.25}$.

Explanation of Solution

Given info:

30 samples of chemical elements were selected Mean is 19.63 and standard deviation is 18.73.

Calculation:

Confidence interval:

Software Procedure:

Step by step procedure to obtain the 90% confidence interval for the mean number of isotopes using the MINITAB software:

• Choose Stat > Basic Statistics > 1-Sample Z.
• In Summarized data, enter the sample size as 30 and mean as 19.63.
• In Standard deviation, enter a value for s as 18.73.
• Check Options, enter Confidence level as 90.0.
• Choose not equal in alternative.
• Click OK in all dialogue boxes.

Output using the MINITAB software is given below:

From the MINITAB output, the 90% confidence interval for the true mean number of isotopes for all elements with isotopes is $\underset{\_}{14.01<\mu <25.25}$.