Question

An independent-measures research study uses a total of 18 participants to compare two treatment conditions. If the results are used to construct a 90% confidence interval for the population mean difference, then the t values will be ±1.746.a) Trueb) False

Answer 1

Answer:

The answer is false

Step-by-step explanation:

In a sample above 30 obs  like this the confidence interval is defined as

X+- t* (s/sqrt(n)) where X is the mean t the tvalue for a given confidence level, n the size of sample and s standar deviation.

To find de appropiate value of t we must see the T table where rows are degrees of freedom and columns significance level

The significance is obtained:

significance = 1 - confidence level = 1 - 0.9 = 0.10

Degrees of freedom (df) for the inteval are

df = n - 1 = 18 - 1 = 17

So we must look for the value of a t with 17 values and significance of 0.10 which in t table is 1.740 not 1.746 ( thats the t for 16 df)