Question

Multiple Choice Questions (Select the best answer) 1. Which of the following is true? a) Ds=Ps = Qs b) Dso = Ps = Q25 c) Ds=Pso = Q2 d) Dso = Ps = Q2 Answer 2. On an easy test, the mean test score is greater than median test score. The distribution of the test scores is likely to be a) Symmetric b) Negatively skewed c) Positively skewed d) Normal Answer= 3. Normal rule states that the approximate percentage of measurements in a data set that fall within one standard deviation of their mean is: a) 68% b) 95% c) 99.7% d) none of these Answers

Answer 1

1) c is the correct option as we know deciles divide the data into 10 parts and 5th deciles represent the middle most observation that is median. Similarly, Percentile divide the data into 100 parts and 50th percentile represents the nedian. Quartiles divide the data into 4 parts and 2nd quartile is the median.

Hence, D5 = P50 = Q2

2)For a symmetric distribution, mean = median, so answer can't be symmetrical.

Also, we know that for a normal distribution, mean = median = mode. So, it can't be a normal distribution.

Now, since, mean does not lie in the middle ( i.e, mean is not equal to the median) distribution will be skewed.

Also, mean is greater than median, means distribution will be skewed to the right with more observations in the left side and tail lying towards the right, hence it will be positively skewed distribution.

Hence, option (c) is the correct answer.

3) By the Area property of normal curve, the percentage of measurements in the dataset that falls within one standard deviation of their mean is approximately 68%.

Hence, option (a) is the correct option.