Question 1.

10 students participate in Statistics quiz 2, their grades are: 98, 85,89,73,76,85,87,92,85,56 The professor wants to know the standard deviation of the grades

11.6871

11.8761

11.7681

11.1768

11.7861

Question 2.

10 students participate in Statistics quiz 2, their grades are: 98, 85,89,73,76,85,87,92,85,56 The professor wants to know the range of the grades

40

44

42

41

43

Question 3.

Which of the following are measures of central tendency? Select all that apply

mean

median

mode

variance

standard deviation

linear transformation

Question 4

A normal distribution with a mean of 15 and standard deviation of 5. 95% of its area is within__

One standard deviation of the mean

Two standard deviations of the mean

Three standard deviations of the mean

It depends on the value of the mode

Question 5.

Which of the following descriptions of confidence interval is correct? (Select all that apply)

If a 99% confidence interval contains 0, then the 95% confidence interval contains 0

If a 95% confidence interval contains 0, then the 99% confidence interval contains 0

If a 99% confidence interval contains 1, then the 95% confidence interval contains 1

If a 95% confidence interval contains 1, then the 99% confidence interval contains 1

Question 6.

If a statistical test result is not significant at the 0.05 level, then we can conclude

It is not significant at 0.01 level

It is not significant at 0.10 level

It must be significant at 0.01 level

It must be significant above 0.05 level

Question 7.

A researcher believed that there was a difference in the amount of time boys and girls at 7th grade studied by using a two-tailed t test. Which of the following is the null hypothesis?

Mean of hours that boys studied per day was equal to mean of hours that girls studied per day

Mean of hours that boys studied per day was greater than mean of hours that girls studied per day

Mean of hours that boys studied per day was smaller than mean of hours that girls studied per day

Mean of hours that boys studied per day was smaller than or equal to mean of hours that girls studied per day

Not enough information

Question 8

A teacher assumed that the average of grades for a math test was 80. Imagine 20 students took the test and the 95% confidence interval of grades was (83, 90). Can you reject the teacher's assumption?

Yes

No

Not enough information

Question 9

Rachael and Peter are discussing how the mean value and variance affect the distribution graph. As the following graph shows, there are two distributions: A and B

Peter said that the distribution A has fatter tail because its has bigger standard deviation than the distribution B. Rachael''s answer is different:she thinks the distribution A has a smaller standard deviation than the distribution B. Who do you think is right?

Peter

Rachael

Neither of them are right. Distribution A and Distribution B have the same standard Deviation

Question 10

Which of the following descriptions of null hypothesis are correct? (Select all that apply)

A null hypothesis is a hypothesis tested in significance testing

The parameter of a null hypothesis is commonly 0

The aim of all research is to prove the null hypothesis is true

Researchers can reject the null hypothesis if the P-value is above 0.05