SOLUTION:
USING STANDARD NORMAL TABLE
At 90% confidence level
= 1 - 90%
= 1 - 0.90 =0.10
/2
= 0.05
Z/2
= Z0.05 = 1.645
B.
USING STUDENT T TABLE
n = 51
Degrees of freedom = df = n - 1 = 51- 1 = 50
At 99% confidence level the t is ,
= 1 - 99% = 1 - 0.99 = 0.01
/ 2 = 0.01 / 2 = 0.005
t
/2 df = t0.005,50=
2.678
2. Find the critical values, Z-scores, for the following confidence intervals by showing a graph and...
Find the critical values, z-scores, for the following confidence intervals by showing a graph and respective areas: a) 80% z-scores b) 95% t-scores. n = 81
Find the critical values for the following confidence intervals (Z-scores) (Please show your work) a.) 99% b.) 98% c.) 90%
For the following sample sizes and confidence levels, find the t-values suitable for building confidence intervals: a) n = 15; 90%. b) n = 6; 95%. c) n = 19; 99%. d) n = 25; 98%. e) n = 10; 99%. f) n = 41; 90%.
A table of Z scores for confidence intervals 90%, 95%, 99%. Use a standard normal table to practice determining z-scores for: 1- 50% two-sided confidence interval 2- 80% upper confidence interval 3- 70% upper confidence interval
19. Given a test statistic: Zc 2 and the known Z-values for common confidence intervals: 1.645, 1.96, and 2.576 for the 90%, 95% and 99 % confidence levels respectively. Can you reject the null hypothesis at the 95% confidence level? Be sure to define and discuss the test statistic and Z-values in your answer.
CHALLENGE ACTIVITY 5.3.1: Confidence intervals for population proportions. Critical values for quick reference during this activity. Confidence level Critical value 0.90 = 1.645 0.95 z* = 1.960 0.99 2.576 Jump to level 1 In a poll of 1000 randomly selected voters in a local election, 34 voters were against fire department bond measures. What is the 99% confidence interval? (Ex: 0.123 Ex: 0.1230 ] (smaller value, larger value] 2 Check Next Feedback
Find the critical values χ2lower=χ21−α/2 and χ2upper=χ2α/2 that
correspond to 99% degree of confidence and the sample size
n=7.
χ2lower= χ2upper=
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Which of the following confidence intervals for ˆp, taken from the same population, will be the smallest? A. 90% confidence, n = 200 B. 90% confidence, n = 50 C. 99% confidence, n = 200 D. 99% confidence, n = 50
14) Find critical values. a) Find the value from table for the indicated confidence level (by using A-2 table). Draw the curve and show all of your work, like we did in the classroom 80% 85% b) Find the value from Table A - 3 for the indicated confidence level and sample size. 95% confidence and n=19 98% confidence and n-22 c) Find the critical values Xi and X(by using A-4 table) that correspond to the given confidence level and...