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Worker Productivity Incentives


An office manager wonders if her employees put in more hours of work when free bagels are delivered every day.

The manager randomly selects $35$ workers to whom bagels will be delivered and compares the number of hours worked by these individuals to another randomly selected group of $35$ workers who do not receive bagels.

The computer output is below.

Two-Sample T-Test and CI

Sample N Mean StDev SE Mean
Bagels 35 40.56 2.45 0.41
No Bagels 35 39.98 2.23 0.38

Difference = $\mu(1)-\mu(2) $

Estimate for difference: $0.580$

$95\%$ CI for difference: ($-0.538, 1.698$)

T-test of difference = $0$ (vs. not =): T-value = $1.04$
P-value = $0.304$
DF = $67$

What practical conclusion can be made based off this data?


There is strong evidence that bagels do not cause workers to put in more hours.


There is strong evidence that bagels do cause workers to put in more hours.


The evidence is inconclusive, so no conclusions whatsoever can be drawn.


A moderate correlation appears between bagels and worker hours.


Based off this experiment, there is insufficient evidence that bagels cause an increase in worker hours.