Discuss the below:
Q1. A check cashing service found that 5% of all checks submitted to the service were bad. (i.e. they could not be cashed for lack of funds). After instituting a check verification system, a sample of 1124 checks produced only 45 that were bad. Does the evidence exist to affirm that the check verification reduces the probability of bad checks? What p value do you give this test?
Q2. An experiment to explore pain thresholds to electrical shock for males and females results in the follow data summary:
Males Females
Totals 14 10
Average 16.2 14.9
Variance(s2 ) 12.7 26.4
Does the data provide sufficient evidence that the variance in pain thresholds for men and women are different? Use α = .10
Q3. Two different methods of training new employees are tested and the times for assembly of the product are noted.
Standard Procedure New Procedure
N1 = 9 N2 = 9
Y1(bar) = 35.22 Y2(bar) = 31.56
∑ I (y1i - y1(bar)2) = 195.56 ∑I (y2i - y2(bar)2) = 160.22
Is there a difference of the true mean times of assembly based on the two methods? Test at α = .05
Q4. A lab technician wants to compare the breaking strength of three brands of thread. Originally he planned to do more, but he lacked time. The breaking in thread is measured in ounces.
Thread 1 18 16.4 15.7 19.6 16.5 18.2
Thread 2 21.1 17.8 18.6 20.8 17.9 19
Thread 3 16.5 17.8 16.1
Test at α =.05 whether the differences in sample means are significant.