Question

# Researchers watched groups of dolphins off the coast of Ireland in 1998 to determine what activities...

Researchers watched groups of dolphins off the coast of Ireland in 1998 to determine what activities the dolphins partake in at certain times of the day ("Activities of dolphin," 2013). The numbers in table #11.1.6 represent the number of groups of dolphins that were partaking in an activity at certain times of days. Is there enough evidence to show that the activity and the time period are independent for dolphins? Test at the 1% level.

Table #11.1.6: Dolphin Activity

 Activity Period Row Total Morning Noon Afternoon Evening Travel 6 6 14 13 39 Feed 28 4 0 56 88 Social 38 5 9 10 62 Colunm Total 72 15 23 79 189

The hypothesis being tested is:

H0: Activity and the time period are independent

Ha: Activity and the time period are not independent

 Morning Noon Afternoon Evening Total Travel Observed 6 6 14 13 39 Expected 14.86 3.10 4.75 16.30 39.00 O - E -8.86 2.90 9.25 -3.30 0.00 (O - E)² / E 5.28 2.73 18.04 0.67 26.72 Feed Observed 28 4 0 56 88 Expected 33.52 6.98 10.71 36.78 88.00 O - E -5.52 -2.98 -10.71 19.22 0.00 (O - E)² / E 0.91 1.28 10.71 10.04 22.93 Social Observed 38 5 9 10 62 Expected 23.62 4.92 7.54 25.92 62.00 O - E 14.38 0.08 1.46 -15.92 0.00 (O - E)² / E 8.76 0.00 0.28 9.77 18.81 Total Observed 72 15 23 79 189 Expected 72.00 15.00 23.00 79.00 189.00 O - E 0.00 0.00 0.00 0.00 0.00 (O - E)² / E 14.95 4.00 29.03 20.48 68.46 68.46 chi-square 6 df 8.44E-13 p-value

Since the p-value (0.0000) is less than the significance level (0.01), we can reject the null hypothesis.

Therefore, we cannot conclude that the activity and the time period are independent for dolphins.

#### Earn Coins

Coins can be redeemed for fabulous gifts.