Question

The average cost for teeth straightening with metal braces is approximately $5400. A nationwide franchise thinks that its cost is below that figure. A random sample of 28 patients across the country had an average cost of $5250 with a standard deviation of $629. At α = 0.025, can it be concluded that the mean is less than $5400?Solve this hypothesis testing problem by finishing the five steps below.

Answer 1

Here we go........................

$\begin{gathered} \text{Null Hypothesis = H}_0\text{ = }\mu\text{ = 5400} \\ \text{Alternative Hypothesis = H}_1\text{ = }\mu\text{ < }5400\text{ and this is the CLAIM} \\ \text{Degre}e\text{ of fr}eedom\text{ = df = 27} \\ \text{critical value CV = -2.052} \end{gathered}$

finding the test value.....

$t-\text{value = }\frac{5250\text{ - 5400}}{\frac{629}{\sqrt[]{28}}}\text{ = }-1.262$