In a sample of 49 adolescents who served as the subjects in an immunologic study, one variable of interest was the diameter of a skin test reaction to an allergen. The sample mean and standard deviation were 21 and 11 mm erythema, respectively. a. Use a z- or t-distribution? Why?

b. One-sided or two-sided test? Why?

c. Can it be concluded from these data that the population mean is less than 24 mm erythema?

d. What is the range on the p-value?

Step-by-step explanation:

a) We would use a t distribution because the population standard deviation is unknown.

b) it is a one sided test because we are trying to determine if the population mean is less than 24 mm erythema. The lesser than means that it is a left tailed test.

c) To determine the p value, we would apply the formula,

t = (x - µ)/(s/√n)

Where

x = sample mean = 21

µ = population mean = 24

s = samples standard deviation = 11

n = number of samples = 49

t = (21 - 24)/(11/√49) = - 1.91

Since n = 49

Degrees of freedom, df = n - 1 = 49 - 1 = 48

We would determine the p value using the t test calculator. It becomes

p = 0.031

Assuming alpha = 0.05, then

Since alpha, 0.05 > than the p value, 0.031, then we would reject the null hypothesis. Therefore, At a 5% level of significance, it can be concluded from these data that the population mean is less than 24 mm erythema.

d) p value = 0.031

d, x=8

step-by-step explanation:

simplifying

4x + -5 = 2x + 11

reorder the terms:

-5 + 4x = 2x + 11

reorder the terms:

-5 + 4x = 11 + 2x

solving

-5 + 4x = 11 + 2x

solving for variable 'x'.

move all terms containing x to the left, all other terms to the right.

add '-2x' to each side of the equation.

-5 + 4x + -2x = 11 + 2x + -2x

combine like terms: 4x + -2x = 2x

-5 + 2x = 11 + 2x + -2x

combine like terms: 2x + -2x = 0

-5 + 2x = 11 + 0

-5 + 2x = 11

add '5' to each side of the equation.

-5 + 5 + 2x = 11 + 5

combine like terms: -5 + 5 = 0

0 + 2x = 11 + 5

2x = 11 + 5

combine like terms: 11 + 5 = 16

2x = 16

divide each side by '2'.

step-by-step explanation:

no, her answer is not correct.   we square the lengths of all sides and then determine whether the pythagorean theorem holds here:

9² + 15² = 306.   this is not equal to the square of the longest side ( that square being 395.   answer c is correct.