The leaves of certain plants in the genus Albizzia will fold and unfold in various light conditions. We have taken fifteen different leaves and subjected them to red light for 3 minutes. The leaves were divided into three groups of five at random. The leaflet angles were then measured 30, 45, and 60 minutes after light exposure in the three groups. Data from W. Hughes
Analyze these data to test the null hypothesis that delay after exposure does not affect leaflet angle