A researcher is interested in whether infants’ attention to their mothers’ voice

Question

A researcher is interested in whether infants’ attention to their mothers’ voices increases in the first week of life. Let’s assume an established baseline exists showing that infants attend to their mothers, on average, for 5.867 seconds on their first day. The researcher selects 15 full-term infants in normal health who experienced uncomplicated deliveries and tests the number of seconds the infants oriented in the direction of their mother’s voice on Day 7 after delivery. Here are the results: 7, 7, 6, 8, 8, 8, 8, 8, 6, 7, 7, 7, 7, 8, 6. Test the hypothesis that attention to the mother’s voice increases over the first 7 days of life, using alpha=.05.

a. What are the hypotheses in formal statistical notation?

b. Draw the distribution/rejection region(s)/critical value(s).

c. Compute the test statistic and show where it falls on your distribution in part b.

d. Make a decision and communicate the results.

Explanation / Answer

The data stats as calculated in excel are

we can perform the t test as follows

t = (xbar-mu)/(sd/sqrt(n)) given mu = 5.867

=(7.2-5.867)/(0.748/sqrt(15)) = 6.901

the hypothesis is

H0 Mean is 5.867
H1 mean is > 5.867

now the df = n-1 = 15-1 = 14 and the alpha is 0.05

so we check the t table for the critical value for 1 tail test as

t-value (right-tail):   1.7613

as the t stat > t critical , hence we reject null in favor of alternate hypothesis and conclude that infants’ attention to their mothers’ voices increases in the first week of life

data 7 Mean 7.2 7 SD 0.748331 6 n 15 8 8 8 8 8 6 7 7 7 7 8 6

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.