1.555
With 88% confidence, there is 6% (0.06) in either tail of the standard Normal distribution. Table C will not help here. Using Table A the correct z* is about halfway between 1.55 and 1.56. According to technology, z*=1.555
norminv([(1-0.86)/2 1 - (1-0.86)/2], 0, 1) which results in a z-score range of -1.4758 to 1.4758
The value is 0.3055
z = ±0.44
No. The width of the confidence interval depends on the confidence level. The width of the confidence interval increases as the degree of confidence demanded from the statistical test increases.
For a two-tailed interval, they are -1.645 to 1.645
1.75
1.31
The answer will depend on whether the critical region is one-tailed or two-tailed.
The answer depends on whether the interval is one-sided or two-sided and, if two-sided, whether or not it is symmetrical.
It depends on whether the interval is one sided or two sided. The critical value for a 2-sided interval is 1.75
The value for a one-sided confidence interval of 86% is 1.08
norminv([(1-0.86)/2 1 - (1-0.86)/2], 0, 1) which results in a z-score range of -1.4758 to 1.4758
The user selects the confidence level. It could also be 90 or 99 or 99.9 or another value.
Z = ± 1.8119 gives a two-tailed interval of 93%
The value is 0.3055
The Z-value for a one-sided 91% confidence interval is 1.34
1.96