The mean weight of a litter of puppies is 7.1 pounds, with a standard deviation of 1.2 pounds. Carly wants to know the weight of the puppy she is buying, but the seller only has the z-score of - 0.25. How much does the puppy weigh?

6.8 pounds

7.4 pounds

5.9 pounds

8.3 pounds

7.3 pounds

Answer: 6.8 pounds

Step-by-step explanation:

Assuming the weight of a litter of puppies is normally distributed, we would apply the formula for normal distribution which is expressed as

z = (x - µ) / σ

Where

x = weight of a liter of puppies.

µ = mean weight

σ = standard deviation

From the information given,

µ = 7.1 pounds

σ = 1.2 pounds

the seller only has the z-score of - 0.25, looking at the probability distribution table, the z score corresponding to the 0.25 is

- 0.68

Therefore,

- 0.25 = (x - 7.1) / 1.2

Cross multiplying by 1.2, it becomes

- 0.25 * 1.2 = x - 7.1

- 0.3 = x - 7.1

x = - 0.3 + 7.1

x = 6.8