A study is conducted to determine the effects of a new drug to enhance neural simulation in the brain for patients suffering from slow neuron firing.The study uses the method of electrophysiology which uses a series of electrodes to measure the changes in membrane voltage (mV). A random sample of 20 patients is measured before being given the drug and again afterwards, with the following output being produced in MINITAB to statistically test if there is a significant increase.

(a)Statistically test at a 1% level of significance whether there is an increase in membrane voltage (mV) to increase neural simulation. Use the appropriate test and state your conclusion. Show all the steps for a hypothesis test.

(b)Suppose the sample size was increased to 30 and the values of the sample mean, and standard deviation remained the same. Test at the 5% level of significance whether there has been an increase membrane voltage (mV) to increase neural simulation.

Probability Plot of After-Before Normal 99 Mean 8.250 S Dev 6.945 95 N 20 AD 0.747 90 . .'. . P- Value 0.043 80 70 Percent 8658 20 10 5 - 10 -5 10 15 20 25 After-BeforeMethod 1 u: mean of AfterBefore Test Null hypothesis Ho: Alternative hypothesis H1: TValue PValue 5.31 0.000 Method 2 n: median of AfterBefore Test Null hypothesis Ho: Alternative hypothesis H1: Sample Number 0 PValue AfterBefore l 0 19 0.000 Method 3 n1: median of After n2: median of Before Difference: n1 - n2 Test Null hypothesis Alternative hypothesis H1: WValue PValue 580.00 0.000