Question 1077671: P value tcdf(2.45,99,10) not working
REM (rapid eye movement) sleep is sleep during which most dreams occur. Each night a person has both REM and non-REM sleep. However, it is thought that children have more REM sleep than adults†. Assume that REM sleep time is normally distributed for both children and adults. A random sample of n1 = 11 children (9 years old) showed that they had an average REM sleep time of x1 = 2.5 hours per night. From previous studies, it is known that σ1 = 0.6 hour. Another random sample of n2 = 11 adults showed that they had an average REM sleep time of x2 = 1.70 hours per night. Previous studies show that σ2 = 0.9 hour. Do these data indicate that, on average, children tend to have more REM sleep than adults? Use a 1% level of significance.
(a) What is the level of significance?
.01
Correct: Your answer is correct.
State the null and alternate hypotheses.
H0: μ1 = μ2; H1: μ1 < μ2
H0: μ1 = μ2; H1: μ1 ≠ μ2
H0: μ1 = μ2; H1: μ1 > μ2
H0: μ1 < μ2; H1: μ1 = μ2
Correct: Your answer is correct.
(b) What sampling distribution will you use? What assumptions are you making?
The Student's t. We assume that both population distributions are approximately normal with known standard deviations.
The standard normal. We assume that both population distributions are approximately normal with unknown standard deviations.
The standard normal. We assume that both population distributions are approximately normal with known standard deviations.
The Student's t. We assume that both population distributions are approximately normal with unknown standard deviations.
Correct: Your answer is correct.
What is the value of the sample test statistic? (Test the difference μ1 − μ2. Round your answer to two decimal places.)
2.45
Correct: Your answer is correct.
(c) Find (or estimate) the P-value. (Round your answer to four decimal places.)
.0171
Incorrect: Your answer is incorrect.
THank you!
Found 2 solutions by Boreal, ikleyn:
Answer by Boreal(15235)   (Show Source):
You can put this solution on YOUR website! This is a one way test, so the p-value calculated is half of what is found using the value of the test statistic. For a test stat of 2.45, which I do get, there is a p-value of 0.0142 using a two way test (equal, not equal) and 0.0071 (0.007083983 is the calculator output)using a one way test.
Answer by ikleyn(52832)  (Show Source):
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