Question

The quantitative data set under consideration has roughly a​ bell-shaped distribution. Apply the empirical rule to answer the following question. A quantitative data set of size 80 has mean 50 and standard deviation 5. Approximately how many observations lie between 45 and 55​? Approximately nothing observations lie between 45 and 55. ​(Round to the nearest whole number as​ needed.)

Answer 1

Sample size (n) = 80

Since we know that


x1 = 45
x2 = 55
P(45.0 < x < 55.0)=?

This implies that

Probability of values lying between 45 and 55 = 1

This means all the 80 values lies in between 45 & 55

AND nothing is outside these two limits

PS: you have to refer z score table to find the final probabilities.
Please hit thumbs up if the answer helped you