Wednesday

October 7, 2015
Posted by **taryn** on Wednesday, March 18, 2009 at 10:12pm.

(N = 561) a week before the election and find that 57% of the respondents prefer

candidate A. Can you predict the winner (α = 0.01)? (Hint: Use 50% as the proportion

of votes needed for a tie in a two-candidate race). [15 points]

3) A random sample of 97 Chinese Americans has finished an average of 13.5 years of

formal education with a standard deviation of 1.7 years of formal training. The national

average is 12.4 years. State a null and alternative hypothesis regarding a possible

difference in years of formal education between Chinese Americans and the whole

population? Can you reject your null hypothesis for α=0.05 (two-tailed)? [10 points]

4) The overall proportion of turnout in the previous elections was 0.43. You took a

random sample of size N =150 from a neighborhood with relatively wealthy and well

educated people. The sample proportion of voter turnout is = 0.51 S P .

a) State a null hypothesis and alternative hypothesis regarding a possible difference in

voter turnout between your sample and the whole population. [5 points]

b) Test your hypotheses (α=0.05, two-tailed). Can you reject your null hypothesis? Does

your decision change when you use α=0.01 (two-tailed) instead? [10 points]

c) Based on your research results from the first sample, you decide to take another sample

from a neighborhood with relatively poor and less educated people. The sample size is

177 2 N = and the sample proportion of voter turnout is 0.37 2 = S P . Can both samples be

treated as representatives of the same population? State a null hypothesis and alternatives

hypothesis and make a statistical test (two-tailed, for both α=0.05 and α=0.01). [15

points]

5) For 2006, a sample of SAT scores of = 1,751 female N female freshmen has mean scores

of female, verbal = 493.7

S μ for the verbal subtest and female, math = 501.2

S μ

for the math subtest,

with standard deviations s female, verbal = 99 and s female, math =111, respectively. Moreover,

the mean scores of a sample of = 2,577 male N male freshmen are male, verbal = 503.9

S μ

for

the verbal subtest and male, math = 542.9

S μ

for the math subtest, with standard deviations

smale, verbal =115 and smale, math = 95, respectively.

a) State a null hypothesis and alternative hypothesis about possible differences in scores

between the female and male samples for the verbal subtest, make a statistical test (use

α = 0.05, two-tailed) and, finally, make your decision between both hypotheses.

[15 points]

b) Do the same thing as in a), but now for the math subtest

- statistics -
**Ms. Sue**, Wednesday, March 18, 2009 at 10:20pmHow would you like us to help you with this complex assignment?