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The resting heart rates for 80 women aged 46–55 in a simple random sample are normally distributed, with a mean of 71 beats per minute and a standard deviation of 6 beats per minute. Assuming a 90% confidence level (90% confidence level = z-score of 1.645), what is the margin of error for the population mean?

Respuesta :

Given:
Confidence level = 90%
mean = 71 beats per minute
standard deviation = 6 beats per minute

margin of error = z * δ / √n

where : δ - population of the standard deviation, n is the sample size ; z is the appropriate z value.

90% confidence level = 1.645 in z-value

margin of error = 1.645 * (6/√80) = 1.645 * (6/8.94) = 1.645 *  0.671 = 1.104

Using the t-distribution, it is found that the margin of error for the population mean is of 1.1 beats per minute.

We have the standard deviation for the sample, hence the t-distribution is used to solve this question.

What is a t-distribution confidence interval?

The confidence interval is:

[tex]\overline{x} \pm t\frac{s}{\sqrt{n}}[/tex]

In which:

  • [tex]\overline{x}[/tex] is the sample mean.
  • t is the critical value.
  • n is the sample size.
  • s is the standard deviation for the sample.

The margin of error is given by:

[tex]M = t\frac{s}{\sqrt{n}}[/tex]

Considering the standard deviation and the sample size, we have that [tex]s = 6, n = 80[/tex].

The critical value is t = 1.645.

Hence:

[tex]M = 1.645\frac{6}{\sqrt{80}} = 1.1[/tex]

The margin of error for the population mean is of 1.1 beats per minute.

You can learn more about the t-distribution at https://brainly.com/question/25256953