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Chapter 7: Q7 (page 350)

Requirements A quality control analyst has collected a random sample of 12 smartphone batteries and she plans to test their voltage level and construct a 95% confidence interval estimate of the mean voltage level for the population of batteries. What requirements must be satisfied in order to construct the confidence interval using the method with the t distribution?

Short Answer

Expert verified

The following two requirements should be satisfied to construct a confidence interval estimate using the student’s t distribution:

  • Randomly selected sample
  • Unknown sigma value
  • The population should be normally distributed.

Step by step solution

01

Given information 

A sample of smartphone batteries of size equal to 12 is selected.

The mean voltage of the batteries is to be estimated using a 95% confidence interval.

02

Requirements

The following requirements need to be satisfied to construct a confidence interval estimate using the student’s t distribution:

  • The sample should be a simple random sample.
  • The standard deviation of the population must be unknown; that is, σis not defined.
  • The population from which the sample data is chosen should be normally distributed.

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