Question

Several science students used the same design when constructing a bridge out of balsa wood. They each tested the bridge's weight capacity using cups filted with sand. The weight capacities were recorded, and the results follow a normal distribution curve. The mean of the weighs is 19.6 lb with a standard deviato n of 1.3 lb. Which weight is greater than 70% of the data?

Answer 1

Answer: 1. B) 0.0611

2. B) 2.79

3. C) 433.5 and 457.4

4. D) 11.25 and 11.81

5. A) 0.6772

6. C) 0.1379

7. C) 137.8

8. D) 0.9564

9. B) 20 and 25

10. D) 20.29

Step-by-step explanation: 100% for stats quiz (please be aware that not all stats quizzes look the same!) :)

Answer 2

Answer:

We are given:

$\mu = 19.6$

$\sigma = 1.3$

We have to find the weight which is greater than 70% of the data.

The z value which corresponds to 70% of the area on the standard normal table is:

$z(0.70) =0.52$

Now, the weight  which is greater than 70% of the data is:

$z=\frac{x-\mu}{\sigma}$

$0.52=\frac{x-19.6}{1.3}$

$0.52 \times 1.3 = x - 19.6$

$x=19.6+0.676$

$x=20.28$ rounded to two decimal places

Therefore, the weight which is greater than 70% of the data is 20.28 lb