The Bureau of Labor Statistics reported that the yearly income of dentists in th

Question

The Bureau of Labor Statistics reported that the yearly income of dentists in the year 2012 was $110,000. A sample of 81 dentists, which was taken in 2013 income of $ 120,000. Assume the standard deviation of the population of dentists' incomes in 2013 is $ 36,000. a. We want to test to determine if there has been a significant increase in the average yearly income of dentists. Provide the null and the alternative b. Compute the test statistic. c. Determine the P - value: and at 95% confidence, test the hypothesis.

Explanation / Answer

null hypothesis: mean =110000

alternate hypothesis: mean >110000

b) std error of mean =std deviation/(n)1/2 =4000

hence test stat z=(X-mean)/std error =(120000-110000)/4000 =2.5

c) p value =0.0062

for p value is less then 0.05 level we reject null hypothesis.

There is sufficient evidence to conclude that mean has increased in 2013.

for 95% CI, z=1.96

hence confidence interval =sample mean -/+ z*Std error =112160.1 ; 127839.9

Related Questions

Navigate

• Browse (All)
• Browse T
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.