In the spring of 2016, he develops on-line videos as a supplement to his class lecture. During that semester, his average grade is 71% from a sample of 49 students. The level of significance is 2.5%. What is the correct conclusion?a. Reject the null hypothesis, conclude the grades improvedb. Fail to reject the null hypothesis, conclude the grades did not improve
c. Reject the null hypothesis, conclude the grades did not improve
d. Fail to reject the null hypothesis, conclude the grades did improve

(c) Reject the null hypothesis, conclude the grades did not improve.

Step-by-step explanation:

Null hypothesis: The grades improved.

Alternate hypothesis: The grades did not improve.

Test statistic (z) = p ÷ sqrt[p(1-p) ÷ n]

p is sample proportion = 0.71

n is sample size = 49 students

z = 0.71 ÷ sqrt[0.71(1-071) ÷ 49] = 0.71 ÷ 0.065 = 10.92

The test is a two-tailed test. At 2.5% significance level, the critical values are -1.96 and 1.96.

Conclusion:

Reject the null hypothesis because the test statistic 10.92 falls outside the region bounded by the critical values -1.96 and 1.96.

Since the null hypothesis is rejected, it therefore means the grades did not improve.

2 & 7

step-by-step explanation:

he climbs 300 ft/hr at a constant rate. the peak is at 1,500 ft.

when going up, he reaches 600 ft in 2 hours. remember, that he is going in a constant rate. divide 600 with 300:

600/300 = 2

assuming that he takes the same route back (meaning that it's a 1500 ft route back, you can solve.

note also that you are solving when he gets back to 600 ft after he reaches the peak.

first, find the amount of hours it takes to get up the peak. divide the total amount (1500), with the ft/her (300) to get the amount of hours (x):

1500/300 = x

x = 5

it takes jamie 5 hours to get up. now, he is returning down, and reaches 600 (his current destination). remember that he climbs at a constant 300 ft/hr. divide 600 with 300:

600/300 = x

x = 2

now add the two numbers together.

x = 5 + 2 = 7

jamie takes 7 hours to go up the mountain and reach his current position when descending.

(total amount/constant rate) = (time).

remember that it is a constant rate, so in total, when he gets back down the mountain, it will take the same amount of time as when he goes up. the total amount for the round trip is: 5 + 5 = 10.

~