Question

Calculate the Z scores of 90% confidence interval, 94% confidence interval, 60% confidence interval.

Answer 1

Answer:

90%= 1.645

94%= 1.880

60%= 0.253

Step-by-step explanation:

from scipy import stats

from scipy.stats import norm

#z-score of 90% confidence interval

stats.norm.ppf(0.95)

#z-score of 94% confidence interval

stats.norm.ppf(.97)

#z-score of 60% confidence interval

stats.norm.ppf(-60)

Answer 2

Concept:

Z-score:

It tells you where the score lies on a normal distribution curve.

It tells how much the value differs from the standard deviation.

It is used to accept or reject the null hypothesis in the hypothesis testing.

Given:

We are given the different confidence intervals:

90%

94%

60%

Find:

We need to find the z- scores at these intervals.

Solution:

For 90% confidence interval:

We have the significance level at 5 % ( as it is a two tailed test)

that is:

α = 5 % = 0.05

z at α = 0.05 from the z table will be:

z = 1.645.

For 94 % confidence interval, we get:

We have the significance level at 3 % ( as it is a two tailed test)

that is:

α = 3 % = 0.03

z at α = 0.03 from the z table will be:

z = 1.555.

For 60 % confidence interval, we get:

We have the significance level at 20 % ( as it is a two tailed test)

that is:

α =20 % = 0.2

z at α = 0.2 from the z table will be:

z = 0.253

Therefore, we get that the z score at 90 % confidence interval is 1.645, at 94 % confidence interval is 1.555 and at 60 % confidence interval is 0.253.

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