Grey-Seal Nursing. Grey seals are one of several types of earless seals. The length of time that a female grey seal nurses her pup is studied by S. Twiss et al. in the article “Variation in Female...

Grey-Seal Nursing. Grey seals are one of several types of earless seals. The length of time that a female grey seal nurses her pup is studied by S. Twiss et al. in the article “Variation in Female Grey Seal (Halichoerus grypus) Reproductive Performance Correlates to Proactive-Reactive Behavioural Types” (PLOS ONE 7(11): e49598. doi:10.1371/journal.pone.0049598). The average lactation (nursing) period of all earless seals is 23 days. A hypothesis test is to be performed to decide whether the mean lactation period of grey seals differs from 23 days.

a. determine the null hypothesis.

b. determine the alternative hypothesis.

c. classify the hypothesis test as two tailed, left tailed, or right tailed.