U.S. politics. Part 2. In the same 2012 survey conducted in Exercise 43, Gallup

Question

U.S. politics. Part 2. In the same 2012 survey conducted in Exercise 43, Gallup reported that 66% of American investors say that the federal budget deficit is hurting the U.S. investment climate “a lot”. Is there any evidence that the percentage has decreased from 79% reported in September 2011? a- Is the z-score of the observed proportion? b- Is there evidence that the proportion has decreased? c- Explain your conclusion Exercise 43 U.S. politics.. Gallup reported in March 2012 that 73% of American investment say that a politically divided federal government is hurting the U.S. investment climate “a lot”. Is there any evidence that the percentage has changed significantly from 74% reported in September 2012? (These results are based on questions asked of a random sample of 1022 U.S adults having investable assets of $1000 or more. # I want to know how to solve the problem using formula not Minitab procedure

Explanation / Answer

(a) p0 = 0.79

H0: p = 0.79

Ha : p < 0.79

here n = 1022

here p is the proportion of people who thing the Federal budget deficit is hurting the US investment climate a lot in October.

standard error of proportion se0= sqrt [0.79 * 0.21/1022] = 0.01274

Z = (p^ - p0)/ se0 = (0.66 - 0.79)/ 0.01274 = - 10.2034

(b) Yes, as l Z l value is greater than the critical z = 1.645 so we can say that the proportion has decreased.

(c) Here we can conclude that there is no probability tof such gallup poll results if true proportion is 0.79 so we can say that the proportion has decreased.

Question 2

p0 = 0.74

H0: p = 0.74

Ha : p 0.74 [ as term not significantly different is used

here n = 1022

here p is the proportion of people who thing the Federal budget deficit is hurting the US investment climate a lot in October.

standard error of proportion se0= sqrt [0.74 * 0.26/1022] = 0.01372

Z = (p^ - p0)/ se0 = (0.73 - 0.74)/ 0.01372 = - 0.73

p- value= 2 * Pr(Z < -0.73) = 2 * 0.2327 = 0.4654

(b) Yes, as l Z l value is lesser than the critical z = 1.96 so we can say that the proportion has not significantly changed.

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