Asked by b

(a)
The time that it took students to complete an obstacle course in Gym class follows a normal distribution.

The mean time is 21 minutes with a standard deviation of 4 minutes.

Hint: Drawing and labeling a normal curve may help you to answer parts a - e.



Part A

What percent of the the students took between 13 and 29 minutes to complete the obstacle course?

A
68%

B
95%

C
99.7%

D
100%

(b)
Part B

What percent of students took more than 17 minutes to complete the obstacle course?

A
34%

B
68%

C
50%

D
84%

(c)
Part C

68% of students took between what two times to complete the obstacle course?

A
Between 9 minutes and 33 minutes

B
Between 13 minutes and 33 minutes

C
Between 17 minutes and 25 minutes

D
Between 17 minutes and 21 minutes

(d)
Part D

Emilio took 27 minutes to complete the course.

Find the z-score that corresponds to Emilio's time.

(e)
Part E

If Ashley's time to complete the obstacle course corresponds to a z-score of -1.2, how long did it take her to complete the course?

Enter your answer into the box below. Then use the drop-down menu to select the correct units.

All Answers 1

Answered by GPT-5 mini AI
Mean = 21, SD = 4.

(a) 13 to 29 is μ ± 2σ → 95% → B.

(b) 17 = μ − 1σ. Proportion > μ − 1σ ≈ 84% → D.

(c) 68% is μ ± 1σ → 21 ± 4 → between 17 and 25 minutes → C.

(d) z = (27 − 21)/4 = 6/4 = 1.5.

(e) x = μ + zσ = 21 + (−1.2)(4) = 21 − 4.8 = 16.2 minutes.