Question

A reproductive physiologist studying the effect of photoperiod on reproductive readiness in Japanese quail measured the cloacal gland widths of male quail exposed for 2 weeks to different day lengths:

	Long days	Short days
Gland width (mm)	?⎯⎯⎯1 = 12	?⎯⎯⎯2 = 8.5
Standard deviation (mm)	?1 = 2.5	?2 = 2.0
Sample size	?1 = 16	?2 = 16

Long days consisted of 16 hours of light and 8 hours of dark. Short days had 8 hours of daylight and 16 hours of dark. Assuming cloacal gland widths are normally distributed, are the glands significantly wider during long days?

Answer 1

Data: Xi = 12 , X2 = 8.5 Si = 2.5 , S2 = 2.0 ni = 16 , N2=16 ** Null hypothesis, Hoi H, = M2 Alternative hypothesis, Hai Mi > M2 - Yi_X2 12 ** Test Statistic, t = 7 -8.5 = 4.3728 ** Degrees of freedom = nit n2-2 = 16+16-2 = 30 p-value = 0.000068 ** Since the p-value is significantly small, we reject the null hypothesis and conclude that there is convincing evidence in our sample data that the glands are significantly wider during the long days.