Question

SAGE MINDTAP WULL HOW Fly 10t? Search this course rk 5: Confidence intervals anment Homework 5: Confidence Intervals Asment Score: 89.18% Save Submit Assignment for Grading Question 4 of 12 Check My Work eBook on Financial, last year fell short According to Thomson Financial, last year the majority of companies reporting profits had beaten estimates. A sample of 162 companies showed that 102 beat estimates, 29 matched estimates, and 31 fell short. (a) What is the point estimate of the proportion that fell short of estimates? If required, round your answer to four decimal places. Pahor 1913 (6) Determine the margin of error and provide a 95% confidence interval for the proportion that beat estimates. If required, round your answer to four decimal places MEⓇ (c) How large a sample is needed if the desired margin of erroris D.OS? If required, round your answer to the next integer om® Mide Feedback Partially Correct Subna Analonment for Gradina
comfidence interval and margin of error

Answer 1

a. Here

Pshort = 0.1913

b. For 95% CI, z value is 1.96 as P(-1.96<z<1.96)=0.95

So Margin of error is

E = 2* = 1.96 * 0.1913 * 0.8087 -= 0.0606 162 V n

So CI is

CI = PIE=0.1913 + 0.0606 = (0.1307,0.2519)

c. For Margin of Error to be 0.05, we will find n using formula of E

E = 2* P9 n

So

n= ()2 *p*9= .06 )2 +0.1913 # 0.8087 = 237.72 = 238