Homework: Review for At Home Quiz #2 Score: 0 of 1 pt 7.2.26 Save 5 of 15 (11 co

Question

Homework: Review for At Home Quiz #2 Score: 0 of 1 pt 7.2.26 Save 5 of 15 (11 complete) HW Score: 49 4496, 7 42 of 15 pts Question Help * During a period of 11 years 642 of the people selected for grand jury duty were sa led, and72% of them were immigrants Use the sample data construct a 99% confidence interval estimate of the proportion of grand jury members who were immigrants. Given that among the people eli ble for jury duty, 68 6% of them were immigrants, does it appear that the jury selection process was somehow biased against immigrants? sp(Round to three decimal places as needed ) Enter your answer in the edit fields and then click Check Answer Clear Al Check Answe remaining

Explanation / Answer

Given :-

Sample size (n) = 642,

Sample proportion (p^) = 72% = 0.72,

99% confidence level at alpha=1% then

critical value (Zc)= 2.575

Therefore, the 99% confidence interval for population proportion (p) is ,

p = ( p^ +/- Zc * ?( p^*(1-p^)/n ) )

p = ( 0.72 +/- 2.575* ?( 0.72*(1-0.72)/642 ) )

p = ( 0.72 +/- 0.046 )

=> 0.72 - 0.046 < p < 0.72 + 0.046

=> 0.674 < p < 0.766

68.6 % = 0.686 ..... No, the confidence interval includes the true percentage of immigrants.

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