Question

In a study of the effect of diet on cholesterol, rats were fed several different diets. One diet had 5% added fiber from oat bran. The study report gives results in the form "mean plus or minus the standard error of the mean." This form is very common in scientific publications. For the 9 rats fed this diet, blood cholesterol levels (in milligrams per deciliter of blood) were 89.02 ± 5.26. What are x and s for these 9 rats? (Use 2 decimal places.)

Answer 1

x = 89.02 milligrams

s = 15.78 milligrams

Explanation:

Data provided:

Mean plus or minus the standard error of the mean = 89.02 ± 5.26

Sample size, n = 9 rats

Now,

x is the mean of the sample of 9 rats i.e 89.02 milligrams (as given in the question)

and,

s is the standard deviation

The standard deviation can be calculated using the relation:

Standard error =
`\frac{\textup{Standard deviation}}{√(n)}`

on substituting the respective values, we get

5.26 =
`\frac{\textup{Standard deviation}}{√(9)}`

or

Standard deviation = 5.26 × 3

or

Standard deviation = 15.78 milligrams