High School

Does your body temperature change during the day? Listed below are body temperatures (in °F) of subjects measured at 8:00 am and at 12:00 am.

Construct a 95% confidence interval estimate of the difference between the 8:00 am temperatures and the 12:00 am temperatures. Is body temperature basically the same at both times?

8:00 am: 97.0, 96.2, 97.6, 96.4, 97.8, 99.2
12:00 am: 98.0, 98.6, 98.8, 98.0, 98.6, 97.6

a) Calculate the value of the margin of error E.
b) Construct the confidence interval.

Answer :

The 95% confidence interval is approximately (-1.8871, 1.5537), suggesting no significant difference in body temperature.

To calculate the 95% confidence interval estimate of the difference between the 8:00 am temperatures and the 12:00 am temperatures, we need to follow a few steps:

  • Calculate the difference between each pair of temperatures:

8:00 am - 12:00 am

97.0 - 98.0 = -1.0

96.2 - 98.6 = -2.4

97.6 - 98.8 = -1.2

96.4 - 98.0 = -1.6

97.8 - 98.6 = -0.8

99.2 - 97.6 = 1.6

  • Calculate the sample mean of the differences:

(-1.0 - 2.4 - 1.2 - 1.6 - 0.8 + 1.6) / 6 = -0.1667

  • Calculate the sample standard deviation of the differences:

First, find the sum of squared differences from the mean:

[tex]((-1.0 + 0.1667)^2 + (-2.4 + 0.1667)^2 + (-1.2 + 0.1667)^2 + (-1.6 + 0.1667)^2 + (-0.8 + 0.1667)^2 + (1.6 + 0.1667)^2)[/tex] = 14.8002

Next, divide the sum by (n-1), where n is the number of differences:

14.8002 / (6-1) = 2.9600

Finally, take the square root to get the sample standard deviation:

sqrt(2.9600) ≈ 1.7204

  • Calculate the margin of error (E):

The margin of error can be calculated using the formula:

E = t * (s / sqrt(n))

where t is the critical value from the t-distribution for a 95% confidence interval, s is the sample standard deviation, and n is the number of differences.

For a 95% confidence interval with 5 degrees of freedom (n-1), the critical value is approximately 2.571.

E = 2.571 * (1.7204 / sqrt(6)) ≈ 1.7204

  • Construct the confidence interval:

The confidence interval estimate is given by:

(mean of the differences) ± (margin of error)

-0.1667 ± 1.7204

(-1.8871, 1.5537)

Therefore, the 95% confidence interval estimate of the difference between the 8:00 am temperatures and the 12:00 am temperatures is approximately (-1.8871, 1.5537).

Since this interval includes zero, we cannot conclude with 95% confidence that the body temperature is significantly different at both times.

However, it's important to note that this analysis is based on a small sample size and may not be representative of the population.

Learn more about Confidence interval

brainly.com/question/32546207

#SPJ11

Other Questions