Question

Construct the 95% confidence interval estimate of the mean VAS score for patients given the magnet treatment. Find the Standard error and critical value. construct the 95% confidence interval estimate of the mean VAS score for patients given the sham treatment. You may do the shortcut.

Answer 1

(3.442 ; 6.558)

Explanation:

Given :

Mean score after patient is given the magnet treatment :

Mean score, xbar = 5

Standard deviation, s = 2.4

Sample size, n = 20

The confidence interval :

Mean ± margin of error

Margin of Error = Tcritical * standard error

The critical value at 95%, df = 20 - 1 = 19

Tcritical = 2.093 (T-student distribution)

The standard error = s/√n = 2.4 / √20 = 0.5367

The margin of error = 2.903 * 0.5367 = 1.558

The confidence interval :

Xbar ± Margin of error

5 ± 1.558

(3.442 ; 6.558)