As part of a study investigating the effects of vigorous exercise on risk of coronary heart disease, researchers measured HDL concentrations (mg/dL) in a sample of 19 male marathon runners as well as in a sample of 32 men who do not regularly exercise. The data are summarized below: Mean St. Dev. Marathon runners 51.3 mg/dL 14.2 mg/dL Do not exercise 44.0 mg/dL 15.0 mg/dL.

Assuming that the two distributions of HDL concentrations are normally distributed with equal variances, run the appropriate test to determine if there is a significant difference between marathon runners and men who don’t exercise. Use t51*= ± 2.009 Note: Pooled SE = 2.43 mg/dL (2pts)

There is a significant difference between marathon runners and men who don't exercise.

Step-by-step explanation:

Null hypothesis: There is no significant difference between marathon runners and men who don't exercise.

Alternate hypothesis: There is a significant difference between marathon runners and men who don't exercise.

Sample 1 (marathon runners)

mean = 51.3 mg/dL

sd = 14.2 mg/dL

n = 19

Sample 2 (men who don't exercise)

mean = 44 mg/dL

sd = 15 mg/dL

n = 32

Pooled SE = 2.43 mg/L

Test statistic (t) = (mean 1 - mean 2) ÷ sqrt[pooled SE(1/n1 + 1/n2)] = (51.3 - 44) ÷ sqrt[2.43(1/19 + 1/32) = 7.3 ÷ sqrt(0.204) = 7.3 ÷ 0.452 = 16.2

The test is a two-tailed test. The critical value is given as 2.009. For a two-tailed test, the region of no rejection of the null hypothesis lies between -2.009 and +2.009.

Conclusion:

Reject the null hypothesis because the test statistic 16.2 falls outside the region bounded by -2.009 and 2.009.

Therefore, there is a significant difference between marathon runners and men who don't exercise.

pay attention in your classes and concentrate the best thing you can do to raise your test scores is to pay attention when you're supposed to be learning the material: in class!

take good notes.

do your homework.

use mnemonics and other tricks.

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note: the best i know.

the answer for this question is : 360°

step-by-step explanation:

we have been given a triangle   we need to tell which one of these is a triangle below to map onto itself.

360° rotation is the complete rotation which eventually leads to the same figure which is given.

the correct will be, that is 360° that will cause the triangle below to map onto itself.