Our bodies have a natural electrical field that is known to help wounds heal. Does changing the field strength slow healing? A series of experiments with newts investigated this question. In one experiment, the two hind limbs of 12 newts were assigned at random to either experimental (treatment) or control groups. This is a matched pairs design. The electrical field in the experimental limbs was reduced to zero by applying a voltage. The control limbs were left alone. The table on the right shows the rates at which new cells closed a razor cut in each limb, in micrometers per hour. The data can accessed HERE. Let μ1μ1 and μ2μ2 be the mean healing rate of the control and the treatment respectively and μ=μ1−μ2μ=μ1−μ2. We wish to conduct a matched pair two sample tt-test with α=0.05α=0.05. Choose the null hypothesis: Choose the alternative hypothesis: Which of the following is the right way to use t.test procedure for this purpose? A. t.test(x1-x2, conf.level=0.95) B. t.test(x1-x2, mu=0, alternative="greater") Use t.test to conduct the tt-test and list the pp-value. pp-value== Should the null hypothesis be rejected? What type of error has been possibly committed? Ans: Type -
Our bodies have a natural electrical field that is known to help wounds heal. Does changing the field strength slow healing? A series of experiments
with newts investigated this question. In one experiment, the two hind limbs of 12 newts were assigned at random to either experimental (treatment) or control groups. This is a matched pairs design. The electrical field in the experimental limbs was reduced to zero by applying a voltage. The control limbs were left alone. The table on the right shows the rates at which new cells closed a razor cut in each limb, in micrometers per hour. The data can accessed HERE.
Let μ1μ1 and μ2μ2 be the mean healing rate of the control and the treatment respectively and μ=μ1−μ2μ=μ1−μ2. We wish to conduct a matched pair two sample tt-test with α=0.05α=0.05.
- Choose the null hypothesis:
- Choose the alternative hypothesis:
- Which of the following is the right way to use t.test procedure for this purpose?
A. t.test(x1-x2, conf.level=0.95)
B. t.test(x1-x2, mu=0, alternative="greater") - Use t.test to conduct the tt-test and list the pp-value.
pp-value== - Should the null hypothesis be rejected?
- What type of error has been possibly committed?
Ans: Type -
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