Answer 18)
Margin of error = (Upper limit – lower limit) / 2
Margin of error = (94.8 - 79.2) / 2
Margin of Error, E = 7.8
19)
Given that,
Sample mean =
= 25.2
Population standard deviation =
= 2.7
Sample size = n =76
At 90% confidence level the z is ,
= 1 - 90% = 1 - 0.90 = 0.10
/ 2 = 0.10/ 2 = 0.05
Z/2 = Z0.05 = 1.645 ( Using z table )
Margin of error = E = Z/2* ( /n)
E = 1.645* (2.7 / 75)
E = 0.5129
90% confidence interval estimate of the population mean is,
- E < < + E
25.2- 0.5129< < 25.2+0.5129
24.6871< < 25.7129
(24.6871, 25.7129)
Margin of Error, E = 0.5129
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