Question

The income of a group 10000 persons were found to be normally distributed with the mean Rs. 520 and standard deviation Rs 60. Find (i) the number of persons having income between Rs 400 & Rs 550

Answer 1

To find the number of persons with incomes between Rs 400 and Rs 550, calculate the z-scores for these values and use the normal distribution table.

Step-by-step explanation:

To find the number of persons with incomes between Rs 400 and Rs 550, we need to calculate the z-scores for these values and use the normal distribution table.

The z-score formula is: z = (x - μ) / σ, where x is the value, μ is the mean, and σ is the standard deviation.

For Rs 400: z = (400 - 520) / 60 = -2, and for Rs 550: z = (550 - 520) / 60 = 0.5.

From the normal distribution table, we can find the probability of having a z-score between -2 and 0.5. This represents the number of persons with incomes between Rs 400 and Rs 550.