Question

What is the normal distribution curve?

How can it be used to aid in the interpretation test?

Answer 1

Solution:

Normal distribution curve: The data of normal distribution when plotted gives us a bell-shaped curve. and it is called the normal distribution curve. The area under this curve is 1 or 100% with 99.72% of the area lying within the three standard deviations of the mean. 68.26% area of the normal distribution lies within one standard deviation of the mean and 95.44% of the area lies within two standard deviations of the mean. The mean of the normal distribution lies at the center of this normal curve which divides the normal curve into two equal halves.50% of the area lies below the mean value and 50% lies above the mean value.

b) The normal curve plays a key role in all the hypothesis test which are based on the normal distribution. We can get a clear picture of what p-value means and how we can find it using the normal curve. Suppose if we got a test statistic for left-tailed one sample z-test for mean, then we can easily find the p-value as:

Because the area below the two standard deviations is 0.023