Hypothesis testing for one sample ttest.
An auditor reviewed 25 oral surgery insurance claims from a particular surgical office, determining that the mean outofpocket patient billing above the reimbursed amount was $275.66 with the standard deviation of $78.11.
(a) At the 5 percent level of significance, does this sample prove a violation of the guideline that the average patient should pay no more than $250 outofpocket? Condition your hypotheses and decision rule.
(b) Is this a close decision?
Hypotheses:

H0: _ = 250 vs. _ > 250

Level of Significance:

5%

Decision Rule

Reject the null hypothesis if pvalue < 0.05

Calculation:

Hypothesis Test: Mean vs. Hypothesized Value

Hypothesized value

250.0000

Mean Sample

275.6600

std. dev.

78.1100

std. error

15.6220

n

25

df

24

t

1.64

pvalue (onetailed, upper)

.0568
