HW 3 1)q8.36 (b) 2)q9.8 3)q9.19 (b) 4)q9.22 (b) 5)q9.46. ======= please help me
ID: 3054833 • Letter: H
Question
HW 3
1)q8.36 (b)
2)q9.8
3)q9.19 (b)
4)q9.22 (b)
5)q9.46.
=======
please help me with this
(( in 20l subject ))
the book I study from is ( statistics:a first course by B.M.perles & J.E.freund)
Explanation / Answer
9.19
a)
CI for = 95%
n = 49
mean = 25.1
z-value of 95% CI = 1.9600
std. dev. = 8.5
SE = std.dev./sqrt(n)
= 8.5/sqrt(49)
= 1.21429
ME = z*SE
= 1.96 * 1.21429
= 2.37996
Lower Limit = Mean - ME
= 25.1 - 2.37996
= 22.72004
Upper Limit = Mean + ME
= 25.1 + 2.37996
= 27.47996
95% CI (22.72 , 27.48 )
b)
CI for = 99%
n = 49
mean = 25.1
z-value of 99% CI = 2.5758
std. dev. = 8.5
SE = std.dev./sqrt(n)
= 8.5/sqrt(49)
= 1.21429
ME = z*SE
= 1.96 * 1.21429
= 3.12779
Lower Limit = Mean - ME
= 25.1 - 2.37996
= 21.97221
Upper Limit = Mean + ME
= 25.1 + 2.37996
= 28.22779
99% CI (21.9722 , 28.2278 )
9.22)
a)
CI for = 90%
n = 60
mean = 72.3
z-value of 90% CI = 1.6449
std. dev. = 8.5
SE = std.dev./sqrt(n)
= 8.5/sqrt(60)
= 1.09735
ME = z*SE
= 1.6449 * 1.09735
= 1.80497
Lower Limit = Mean - ME
= 72.3 - 1.80497
= 70.49503
Upper Limit = Mean + ME
= 72.3 + 1.80497
= 74.10497
90% CI (70.495 , 74.105 )
b)
CI for = 90%
n = 60
mean = 82.3
z-value of 90% CI = 1.6449
std. dev. = 8.5
SE = std.dev./sqrt(n)
= 8.5/sqrt(60)
= 1.09735
ME = z*SE
= 1.6449 * 1.09735
= 1.80497
Lower Limit = Mean - ME
= 82.3 - 1.80497
= 80.49503
Upper Limit = Mean + ME
= 82.3 + 1.80497
= 84.10497
90% CI (80.495 , 84.105 )
9.46)
n = 500
p = 0.15
z-value of 95% CI = 1.9600
SE = sqrt(p*(1-p)/n)
= sqrt (0.15 * (1 -0.15) /500)
= 0.01597
ME = z*SE
= 1.96 * 0.01597
= 0.03130
Lower Limit = p - ME
= 0.15 - 0.03130
= 0.11870
Upper Limit = p + ME
= 0.15 + 0.03130
= 0.18130
95% CI (0.1187 , 0.1813 )
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