Test of two proportions
You may wonder if the amount paid for freight affects whether or not the shipment was late. Recall that in late_shipments dataset, whether or not the shipment was late is stored in the late column. Freight costs are stored in the freight_cost_group column, and the categories are "expensive" and "reasonable".
We can form hypotheses to test.
\(H_{0}\): \(late_{\text{expensive}} - late_{\text{reasonable}} = 0\)
\(H_{A}\): \(late_{\text{expensive}} - late_{\text{reasonable}} > 0\)
p_hats contains the estimates of population proportions (sample proportions) for the "expensive" and "reasonable" groups. ns contains the sample sizes for these groups.
Deze oefening maakt deel uit van de cursus
Hypothesis Testing in R
Praktische interactieve oefening
Probeer deze oefening eens door deze voorbeeldcode in te vullen.
# See the sample variables
print(p_hats)
print(ns)
# Calculate the pooled estimate of the population proportion
p_hat <- ___
# See the result
p_hat