1. A study was conducted to estimate ?, the mean commute distance that all emplo
ID: 3376116 • Letter: 1
Question
1. A study was conducted to estimate ?, the mean commute distance that all employed U.S. adults travel to work. Suppose a random sample of 49 employed U.S. adults gives a mean commute distance of 22 miles and that from prior studies, the population standard deviation is assumed to be ? = 8.4 miles. How large a sample of U.S. adults is needed in order to estimate ? with a 95% confidence interval of length 2.4 miles?
196
49
111
784
2. The probability that z is less than 2 is
0.4772
0.0228
0
0.9772
3. A cry count of newborns and IQ at age three example, finds the following:
The correlation coefficient of our observed data is r = 0.4.
The p-value of the test:
Ho: There is no linear relationship between cry count and IQ.
Ha: There is a significant linear relationship between cry count and IQ.
is p=0.012.
Which of the following statements is true?
The data provide fairly strong evidence of a moderately weak linear relationship between cry count (a few days after birth) and IQ (at age 3) among infants.
The data provide moderately weak evidence of a fairly strong linear relationship between cry count (a few days after birth) and IQ (at age 3) among infants.
The data provide fairly strong evidence of a fairly strong linear relationship between cry count (a few days after birth) and IQ (at age 3) among infants.
The data provide moderately weak evidence of a moderately weak linear relationship between cry count (a few days after birth) and IQ (at age 3) among infants.
a.196
b.49
c.111
d.784
Explanation / Answer
(2) Probability that Z is less than 2 = P(Z < 2) = P(Z <= 2) = 0.9772.
(3) Since p-value is less than alpha = 0.05, the data provide fairly strong evidence of a moderately weak linear relationship between cry count (a few days after birth) and IQ (at age 3) among infants. (Option a)
(1) Sample size = ((1.96 * 8.4)/1.2)2 = 188.2384. Thus, Option a is correct.
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.