Question

15. Previous research states, "no evidence currently exists supporting or refuting the use of electric fans during heat waves" in terms of mortality and illness. Counterintuitively, Public Health guidelines suggest not using fans during hot weather, with some research reporting the potential of fans accelerating body heating.

You decide to research further this seemingly contradictory guidance, hypothesizing that the true population average core body temperature amidst higher ambient temperature and humidity levels while using an electric fan is different than 109 degrees Fahrenheit (°F) and you set the level of significance at 2.5% for your formal hypothesis test. You randomly sample 35 participants based on your research funding and for 45 minutes, the study participants sit in a chamber maintained at a temperature of 108°F (i.e., 42 degrees Celsius) and a relative humidity of 70%. After the first 45 minute warming period, for each participant you place a personal sized electric fan 3 feet away with its airflow directed at a given participant's chest area, and the participants relax in this position for the next 45 minutes. At the end of this 45 minute fan period, you record the core body temperature of all participants. The following table comprises the data you collect.

Subject	Core Body Temperature (°F)
1	95.6
2	95.6
3	94.5
4	94.8
5	95.9
6	94.9
7	97.0
8	95.7
9	95.0
10	95.4
11	95.4
12	94.4
13	96.4
14	95.0
15	96.4
16	94.6
17	96.0
18	94.9
19	95.6
20	95.6
21	96.5
22	95.3
23	94.3
24	95.0
25	95.5
26	95.8
27	94.8
28	96.2
29	95.7
30	94.9
31	93.9
32	94.3
33	95.9
34	96.8
35	95.2

Per Step 5 of the 5-Steps to Hypothesis Testing, choose the appropriate formal and informal conclusions.

Please note the following: 1) you may copy and paste the data into Excel to facilitate analysis; and 2) in the prior question you already calculated a test statistic but on a different dataset – calculate the test statistic again using the dataset directly above in selecting the corresponding formal and informal conclusions.

Select one:

a. We reject H0 because z ≥ -1.645 and z > +1.960, where z = -108.078. We do not have statistically significant evidence at α = 5% to show that the true population proportion of heart and core temperature increases amidst higher ambient temperature and humidity levels is different than 109°F.

b. We reject H0 because z ≤ -2.241 or z ≥ +2.241, where z = -108.078. We have statistically significant evidence at α = 2.5% to show that the true population average core body temperature amidst higher ambient temperature and humidity levels while using an electric fan is different than 109°F.

c. We accept H1 because z = -2.326 and z > -2.326, where z = -108.078. We do not have statistically significant evidence at α = 2.5% to show that the true population proportion of heart and core temperature increases amidst higher ambient temperature and humidity levels is different than 109°F.

d. We do not accept H1 because z = -2.326 or z = +1.645, where z = -108.078. We have statistically significant evidence at α = 2.5% to show that the true population proportion of heart and core temperature increases amidst higher ambient temperature and humidity levels is different than 109°F.

Answer 1

Subject	Temperature (°F)
1	95.6
2	95.6
3	94.5
4	94.8
5	95.9
6	94.9
7	97
8	95.7
9	95
10	95.4
11	95.4
12	94.4
13	96.4
14	95
15	96.4
16	94.6
17	96
18	94.9
19	95.6
20	95.6
21	96.5
22	95.3
23	94.3
24	95
25	95.5
26	95.8
27	94.8
28	96.2
29	95.7
30	94.9
31	93.9
32	94.3
33	95.9
34	96.8
35	95.2
Mean	95.39428571	AVERAGE()
Sd	0.74476323	STDEV()
n	35

Hypothesis:

H0: μ = 109

Ha: μ not = 109

significance level:

alpha = 0.05

Critical value:

Zc = 2.241

rejection region:

z ≤ -2.241 or z ≥ +2.241

Test stat:

Z stat = (X bar-μ)/(Sd/SQRT(n)) = (95.39-109)/(0.7448/SQRT(35)) = -108.078

Decision:

Z stat ≤ -2.241, Reject H0

Conclusion:

b. We reject H0 because z ≤ -2.241 or z ≥ +2.241, where z = -108.078. We have statistically significant evidence at α = 2.5% to show that the true population average core body temperature amidst higher ambient temperature and humidity levels while using an electric fan is different than 109°F.