An experiment was conducted to determine the efficacy of spraying oats with Malathion (at 0.25 lb/acre) to control the cereal leaf beetle. Two fields were used at each of 10 farms in southwest Manitoba. One field at each farm was assigned at random to either the control group (no spray) or the treatment group (spray), and the second field was assigned to the other treatment. At the conclusion of the experiment, a plot on each farm was selected, the number of beetle larvae per square foot was measured, and a one-tailed test of significance was performed to determine if Malathion reduced the number of beetles. The results are given below. [Assume conditions for the appropriate inference procedure have been met]. n
s
Control fields
5
6.20
1.30
Treatment fields
5
4.76
2.49
Control Field – Treatment Field (Pairs)
5
1.44
1.26

In which one of the following cases would a Type II error occur?
a
We conclude Malathion is effective when in fact it is effective.
b
We conclude Malathion is neither ineffective nor effective.
c
We conclude Malathion is effective when in fact it is ineffective.
d
We do not conclude Malathion is effective when in fact it is ineffective.
e
We do not conclude Malathion is effective when in fact it was effective.