Question

3. Listed below are sorted braking reaction times in 1 / 10,000 sec) for male and female subjects (based on data from the RT-2S Brake Reaction Time Tester), also listed in the Excel file: Brake Reaction Time.rlsr. Male 28 30 31 34 34 36 38 38 38 38 39 40 40 40 40 41 41 41 | 42| 42| 40| 46 | 47 | 48 | 48 | 49 51 53 54 56 66 67 60 61 | 61 | 63 | Female 22 24 34 36 36 37 39 41 41 43 43 45 45 47 53 54 54 55 56 57 57 57 58 61 62 63 66 67 68 71 72 76 77 78 79 80 Complete all of the following with the use of Excel (no hand calculation), and provide screen shots for results. (a) Construct a histogram for the reaction times of males. Use a class width of 8 and use 28 as the lower limit of the first class. For the horizontal axis, use class midpoint values. Confirm that the data are from a population with a normal distribution (ie that the sample data appear to be from a population with a distribution that is approximately normal). (b) Construct a modified boxplot of the braking reaction times of males and another modified boxplot for the braking reaction times of females. What do these boxplots suggest? (c) Test the claim that males and females have the same mean, with a 0.01 significance level by following similar steps (a) to (e) from Question 2. (d) Construct a 99% confidence interval estimate of the mean braking reaction time of males, construct a 99% confidence interval estimate of the mean braking reaction time of females, then write a statement about your comparison of the two confidence interval estimates. (e) Construct a 99% confidence interval estimate of the difference between the mean braking reaction time of males and the mean braking reaction time of females. (f) Which is better for comparing the mean reaction times of males ar results from part (d) or the results from part (e)?

Answer 1

ALREADY ANSWERED THIS!!!!! THIS IS THE SECOND TIME!!

(a)

Histogram Percent Male

The data is from a normal distribution.

(b)

BoxPlot 20 30 40 50 60 70 Male

BoxPlot 0 10 20 30 40 50 Female 60 70 80 90

The mean reaction time of females is more than males. The reaction time is greater for females.

(c) The hypothesis being tested is:

H₀: µ₁ = µ₂

H₁: µ₁ ≠ µ₂

The output is:

44.361	mean Male
54.278	mean Female
-9.917	mean difference (Male - Female)
6.674	std. dev.
1.112	std. error
36	n
35	df
-8.916	t
1.56E-10	p-value (two-tailed)

Since the p-value (0.0000) is less than the significance level (0.05), we can reject the null hypothesis.

Therefore, we cannot conclude that males and females have the same mean.

(d) For males:

	Male
count	36
confidence interval 99.% lower	40.06
confidence interval 99.% upper	48.66
margin of error	4.30
t(df = 35)	2.724

For females:

	Female
count	36
confidence interval 99.% lower	47.19
confidence interval 99.% upper	61.36
margin of error	7.09
t(df = 35)	2.724

The confidence interval is greater for females.

(e)

-9.917	mean difference (Male - Female)
-12.946	confidence interval 99.% lower
-6.887	confidence interval 99.% upper
3.030	margin of error

(f) Part (d) is better.