To examine the potential effects on the transmission of dengue, Bian et al. (2010) infected mosquitoes from both the WB1 (laboratory created) strain and the original wild strain with dengue. Fourteen days later, the mosquitoes were allowed to feed on an artificial food solution for 90 minute. Viral titers in the food solution were then measured in plague feeding units per ml. The results are given below. Mosquitoes were tested in groups, and so each data value is an average for the group, measured in plaque feeding units per ml. The data have already been log-transformed using log(Y+1), to better visualize the differences.
WB1: n1 = 8 R1 = 77
Wild: n2 = 6 R2 = 19.5
H0: the distribution of viral titers is the same between the two strains
HA: the distribution of viral titers is not equal
The data has been ranked from smallest to largest andthe rank sum (R1, R2) for each data set are listed above. Carry out a Mann-Whitney U-test on the WB1 data and solve for U1. Answer to one decimal place.
Answer:
Consider,
U1 = n1n2 + (n1(n1+1)/2) - R1
substitute the given values in the above formula
= 8*6 + (8(8+1)/2) - 77
= 48 + 36 - 77
= 7
To examine the potential effects on the transmission of dengue, Bian et al. (2010) infected mosquitoes...
To examine the potential effects on the transmission of dengue, Bian et al. (2010) infected mosquitoes from both the WB1 (laboratory created) strain and the original wild strain with dengue. Fourteen days later, the mosquitoes were allowed to feed on an artificial food solution for 90 minute. Viral titers in the food solution were then measured in plague feeding units per ml. The results are given below. Mosquitoes were tested in groups, and so each data value is an average...
1.) If you have two treatments that are independent samples and you assume a normal distribution of the data, which test(s) would be appropriate to use? Select all that apply. Mann-Whitney U-test Paired t-test Welch's t-test Two-sample t-test Sign test 2.)The [x] is used to test a null hypothesis that the mean difference of paired measurements equals a specified value. 3.) To examine the potential effects on the transmission of dengue, Bian et al. (2010) infected mosquitoes from both the...