Question

Weather affects flights across the nation, causing delays, cancellations, and general disruption to the NAS. You have gathered a random sample of departures delayed due to weather from your airport (KXYZ) for the month of April through July. You know that across America, weather delayed an average of 59 flights per day (σ =34.83) during that time period. You want to know if weather delays on flights from your airport differ significantly from those across the nation. Your significance level is set at 0.05. Analyze the data below using the correct t-test and be sure to check assumptions of the data.

Answer the following questions:

a. What type of t test should be used to address this research question, and why?
b. What is the null hypothesis?
c. What is the alternative hypothesis?
d. What is the mean and standard deviation for amount of the population?
e. What is the mean and standard deviation for the sample?
f. What are the degrees of freedom? How do you compute it?
g. What is the effect size (Cohen’s d) if applicable?
h. What is the test value?
i. What is the t statistic?

Answer 1

a.) one sample t test

b.) H0 : μ = 59.3

c.) H1 : μ > 59.3

d.) μ = 59.3 ; σ = 39.84

e.) xbar = 79.4 ; s = 61.36

Test statistic = 3.16

Explanation:

Given the sample data:

49.00 49.00 49.00 49.00 49.00 63.00 63.00 63.00 63.00 63.00 199.00 199.00 199.00 199.00 199.00 38.00 38.00 38.00 38.00 38.00 48.00 48.00 48.00 48.00 48.00 49.00 63.00 199.00 38.00 48.00

Sample size, n = 30

Using calculator :

xbar from the data above = 79.4

Standard deviation = 61.359

H0 : μ = 59.3

H1 : μ > 59.3

Test statistic :

(Xbar - μ) ÷ (σ/sqrt(n)

σ = 34.83

(79.4 - 59.3) ÷ (34.83/sqrt(30))

20.1 ÷ 6.359

Test statistic = 3.16