Question

The data below gives the survival times of 20 mice exposed to 240 rads of gamma radiation.

152 152 115 109 137 88 94 77 160 165 125 40 128 123 136 101 62 153 83 69

Does the sample evidence support the hypothesis that the median survival time for mice exposed to 240 rads of gamma radiation exceeds 100? (α = 0.05)

Answer 1

here null hypothesis: Ho: =100

alternate hypothesis: Ha: >100

for above given data values more then 100 =13

hence probability of having 13 or more values higher then 100 given median is at 100 =P(X>=13)=1-P(X<=12)

=1- =1-0.8684 =0.1316

as probability of getting such result is not less then 0.05 level of signifcance therefore we can not reject null hypothesis

we do not have sufficient evidence to conclude that median survival time for mice exposed to 240 rads of gamma radiation exceeds 100