In: Statistics and Probability
Feit Electric manufactures 60-watt equivalent Compact Fluorescent Bulbs that it guarantees will last at least 10,000 hours. The Consumer Testing Company tested the claim of the manufacturer by purchasing a random sample of 60-watt equivalent CFBs manufactured by Feit Electric. The Consumer Testing Company tested 36 CFBs. The results of the test are found in Chapter_10_Project_HT_CFB.xlsx. The Consumer Testing Company has no other data on CFBs from the manufacturer, so must rely for its test on the sample of 36 bulbs.
Use Proposed R Code for Part Two 2. and the Excel file Chapter_10_Project_HT_CFB.xlsx. Calculation should be completed in RStudio. For the null hypothesis, assume that the Compact Fluorescent Bulbs satisfy the guarantee of Feit Electric.
(a) State the null and the alternative hypothesis. H0 : µ = Ha : µ [ ≠ or > or < ]
(b) Should the test be a left-tail, right-tail or two- tail test?
(c) Calculate t using the R code for variable tcfb given below. [Proposed R Code for Part Two 2.]
(d) Find the rejection region (critical value) for α = 0.01. What is the decision? [Compare tcfb to tcrit01.] Is the null hypothesis rejected or do the CFBs satisfy the guarantee?
(e) Find the rejection region (critical value) for α = 0.05. What is the decision? Compare tcfb to tcrit05.] Is the null hypothesis rejected or do the CFBs satisfy the guarantee?
DATA.
8800
9155
13001
10250
100002
11413
8234
10402
10016
8015
6110
11005
8550
11555
9254
6991
12006
10420
8302
8151
10980
8694
10186
10003
8814
11445
6277
8632
7265
10584
9397
11987
8502
7556
10380
8582
(a) State the null and the alternative hypothesis. H0 : µ = Ha : µ [ ≠ or > or < ]
The hypothesis being tested is:
H0: µ 10000
Ha: µ < 10000
(b) Should the test be a left-tail, right-tail or two- tail test?
left-tail
(c) Calculate t using the R code for variable tcfb given below. [Proposed R Code for Part Two 2.]
t = 0.779
(d) Find the rejection region (critical value) for α = 0.01. What is the decision? [Compare tcfb to tcrit01.] Is the null hypothesis rejected or do the CFBs satisfy the guarantee?
Reject Ho if t < -2.44.
Since 0.779 < 2.44, we fail to reject the null hypothesis.
Therefore, we can conclude that µ 10000.
(e) Find the rejection region (critical value) for α = 0.05. What is the decision? Compare tcfb to tcrit05.] Is the null hypothesis rejected or do the CFBs satisfy the guarantee?
Reject Ho if t < -1.69.
Since 0.779 < 1.69, we fail to reject the null hypothesis.
Therefore, we can conclude that µ 10000.