Unbiased Sample? Suppose you attend a school that offers both traditional course
ID: 3217590 • Letter: U
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Unbiased Sample? Suppose you attend a school that offers both traditional courses and online courses. You want to know the average age of all the students. You walk around campus asking those students that you meet how old they are. Would this result in an unbiased sample? Gender: Randomly Chosen? A large community college district has 1000 teachers, of whom 50% are men and 50% are women. In this district, administrators are promoted from among the teachers. There are currently 50 administrators, and 70% of these administrators are men. a. If administrators are selected randomly from the faculty, what is the approximate probability that the percentage of male administrators will be 70% or more? b. If administrators are selected randomly from the faculty, what is the approximate probability that the percentage of female administrators will be 30% or less? c. How are part a and part b related? d. Do your answers suggest that it is reasonable to believe the claim that the administrators have been selected randomly from the teachers? Answer yes or no, and explain your answer. Do People Think the Sun Goes around the Earth? In the 2012 General Social Survey, people were asked whether they thought the sun went around the planet Earth or vice versa. Of 1974 people, 203 thought the sun went around Earth. a. What proportion of people in the survey believed the sun went around Earth? b Find a 95% confidence interval for the proportion of all people with this belief. c. Suppose a scientist said that 30% of people in the general population believe the sun goes around Earth. Using the confidence interval, would you say that was plausible? Explain your answer.Explanation / Answer
Q7.62
a.
no.of though sun went around(x)=203
Sample Size(n)=1974
Sample proportion = x/n =0.103
b.
Confidence Interval For Proportion
CI = p ± Z a/2 Sqrt(p*(1-p)/n)))
x = Mean
n = Sample Size
a = 1 - (Confidence Level/100)
Za/2 = Z-table value
CI = Confidence Interval
Confidence Interval = [ 0.103 ±Z a/2 ( Sqrt ( 0.103*0.897) /1974)]
= [ 0.103 - 1.96* Sqrt(0) , 0.103 + 1.96* Sqrt(0) ]
= [ 0.09,0.116]
c.
0.30 is n't be possible as it is out of bound to the interval achived
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