Question

4. The values listed are waiting times (in minutes) of customers at the Jefferson Bank., where customers enter a single waiting line that feeds three teller windows. Find the critical values 2 and z corresponding to a 95% confidence level. 6.5 6.6 6.7 6.8 7.1 7.3 7.4 7.7 7.7 7.7 O 3.325, 16.919 O 2.700, 19.023 O 3.247, 20.483 O1.237, 14.449 5. Find the 99% confidence interval for the population standard deviation given the following, (1 point) n-17, R 472,s -26.9 and the distribution is normal. 3.5 < σ < 9.1 30.0 < ơ < 38.2 (0 322.5 σ« 832,6 18.4< Ơc47.5 6. What are the critical values that correspond to a 9596 c onfidence level and a sample size of 93? (4 point 65.647, 118.136 59.196, 128.299 57.143, 106.629 69.196, 113.145 Construct a 99% confidence interval for the population standard deviation of white blood cell count (in cells per microliter), Assume 7 distribution. The sample has a mean of 7.106 cells and a standard devistion of 2.019 cells random samples were selected from a populstion that has a normal (1 point 1.098 σ< 4.973 4.042 « σ < 21.170 1.148 Ơ< 6.015 1.319 ơ 36.181

Answer 1

Solution:-

9) 90% confidence interval for the population standard deviation is $2.024< \sigma < 2.785$ .

$\bar{x}=11.49,s=2.34,n=55$

$\sqrt{\frac{s^{2}(n-1)}{\chi^{2}_{\alpha /2} }}< \sigma < \sqrt{\frac{s^{2}(n-1)}{\chi^{2}_{1-\alpha /2} }}$

$\sqrt{\frac{(2.34)^{2}(55-1)}{72.15 }}< \sigma < \sqrt{\frac{(2.34)^{2}(55-1)}{38.12 }}$

$2.024< \sigma < 2.785$

10) The critical values for 98% confidence interval is (4.107, 27.688).

n = 14

D.F = n - 1

D.F = 13

$\chi ^{2}_{L} = 4.107$

$\chi ^{2}_{L} = 27.688$