Confidence interval for a mean Quiz
10 questions · easy to harder · University Statistics · score and step-by-step answers
How it works
- 10 questions, about 30 minutes (a timer counts down; you can hide it). Solve it right here: no sign-up.
- 3 questions have choices. For the others you type the answer: a number like 4, −2, 7/2 or 3.5, or for example x = 4, x = 2 or x = −3, (3, 5), 2x + 1. Use ^ for powers (x^2) and sqrt for √. Any form with the same value counts (7/2 = 3.5).
- One question at a time: Back, Next, Mark for review and the question list at the bottom. A calculator is on the screen.
- At the end: your percent and grade, every question right or wrong, why a wrong choice is wrong, and its step-by-step solution. Then practise the lesson with new questions.
Your answers and results are kept in this browser only, so you can close the page and come back.
1 Question 1
Calculate 95% confidence interval: mean 50, sd 8, n 64- A) (48.04, 51.96)
- B) (49.755, 50.245)
- C) (51.96, 48.04)
2 Question 2
Calculate 90% confidence interval: mean 40, sd 6, n 36Type the answer.
3 Question 3
Calculate 90% confidence interval: mean 70, sd 10, n 25- A) (73.29, 66.71)
- B) (66.71, 73.29)
- C) (69.342, 70.658)
4 Question 4
Calculate 95% confidence interval: mean 100, sd 20, n 100Type the answer.
5 Question 5
Calculate 95% confidence interval: mean 64.5, sd 7, n 49- A) (66.46, 62.54)
- B) (62.54, 66.46)
- C) (64.22, 64.78)
6 Question 6
Calculate 95% confidence interval: mean 250, sd 40, n 100Type the answer.
7 Question 7
Calculate 90% confidence interval: mean 36, sd 9, n 81Type the answer.
8 Question 8
Calculate 95% confidence interval: mean 12.5, sd 3, n 50Type the answer.
9 Question 9
Calculate 99% confidence interval: mean 4.2, sd 0.6, n 64Type the answer.
10 Question 10
Calculate 90% confidence interval: mean 5.6, sd 1.5, n 20Type the answer.