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