3 pages total - Statistical Essay

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week_9_assignment.xlsx

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(1) 95% confidence interval
sample of size 76, 41 people believed
n=76, x=41
p =41/76= 0.5395
95% interval = (p ̅- Z_(α/2) √((p ̅*(1-p ̅))/n), p ̅+ Z_(α/2) √((p ̅*(1-p ̅))/n))
95% confidence level Zα/2 = 1.96
95% confidence interval as (0.5395-1.96*√((0,5395*(1-0.5395))/76) , 0.5395+1.96*√((0,5395*(1-0.5395))/76) ) = (0.4274, 0.6515).
Null Hypothesis H0: people who believe is less than/equal 0.5. H0: p ≤ 0.5 (Upper tail)
Alternative greater than 0.5. H1: p > 0.5 (claim)
α =0.05
Z =
Zα =1.645 region Z > 1.645
Substituting the value Z = (((41/76)-0.5))/√((0.5(1-0.6))/76) =0.688
(2) 95% sample of size 76, 40 people keep up with space exploration events
n=76, x=40
=40/76= 0.5263. The 95%
confidence people who keep up:
(,
standard deviation:
Zα/2 = 1.96
(0.5263-1.96* , 0.5263+1.96* ) = (0.4141, 0.6386)
null hyp: less than or equal to 0.5. H0: p ≤ 0.5 (Upper tail)
alternative: greater than 0.5. H1: p > 0.5 (claim) Significance level α =0.05 Test statistic Z = ((p ̅-p))/√((p(1-p))/n) follows a standard normal distribution
Zα =1.645 region Z > 1.645
sub Z = (((40/76)-0.5))/√((0.5(1-0.6))/76) =0.4588

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