Question

5.

California and Washington state both started reporting COVID-19 cases at approximately the same time. Suppose a researcher wants to study the fatality rate of diagnosed COVID-19 cases in the 2 states.

a. What null hypothesis should be used? Pick one and explain.

i. California has a higher fatality rate than Washington.
ii. California has lower higher fatality rate than Washington.
iii. California has a different fatality (possibly higher, possibly lower) rate than Washington. iv. California and Washington have the same fatality rate.

b. What alternate hypothesis should be used? Pick one and explain.

i. California has a higher fatality rate than Washington.
ii. California has lower higher fatality rate than Washington.
iii. California has a different fatality (possibly higher, possibly lower) rate than Washington. iv. California and Washington have the same fatality rate.

c. As of 3/24/2020, California had 2220 cases and 100 fatalities, compared to 111 fatalities in 2221 cases in Washington. Use your calculator to carry out a suitable hypothesis test. Report the p-value of the test, determine whether or not to reject the null, and state what should be concluded. Use ? = .05.

Answer 1

Ans 5 )

a. the null hypothesis should be used is

iv. California and Washington have the same fatality rate.

becasue the claim is that California and Washington state both started reporting COVID-19 cases at approximately the same time

b. the alternate hypothesis should be used
iii. California has a different fatality (possibly higher, possibly lower) rate than Washington.

c.

Z Test for Differences in Two Proportions
Data
Hypothesized Difference	0
Level of Significance	0.05
Group 1
Number of Items of Interest	100
Sample Size	2220
Group 2
Number of Items of Interest	111
Sample Size	2221
Intermediate Calculations
Group 1 Proportion	0.045045045
Group 2 Proportion	0.049977488
Difference in Two Proportions	-0.00493244
Average Proportion	0.0475
Z Test Statistic	-0.7726
Two-Tail Test
Lower Critical Value	-1.9600
Upper Critical Value	1.9600
p-Value	0.4398
Do not reject the null hypothesis

let p1 =population  proportion of fatality in California.

p2 = population proportion of fatality in Washington .

Ho:p1= p2

Ha:p1 p2

the p-value of the test is 0.4398

since p value is greater than 0.05 so we do  not reject the null hypothesis and conclude that the fatality rate is same in California and Washington