Step-1

Title: Normal distribution

Grade: 9-a Lesson: S4-L9

Explanation: Hello Students, time to practice and review the steps for the problem.

Step Type Explanation Answer

1

Problem

A radar unit is used to measure speeds of cars on a motorway. The speeds are normally distributed with a mean of 90 km/hr and a standard deviation of 10 km/hr. What is the probability that a car picked at random is travelling at more than 100 km/hr?

2

Formula:

\$Z = (X-\mu )/ \sigma\$

3

Step

From the given data

\$\mu = 90 , \sigma = 10 , X = 100\$

4

Clue

Probability that a car picked at random is travelling at more than 100 km/hr

P(X>100)

5

Step

Converting to standard normal curve

\$P(X>100) = P((X-\mu )/ \sigma) > (100-90 )/ 10)\$

\$P(X>100) = P(Z>1)\$

6

Step

P(Z>1)

[Total area] - [area to the left of z=1]

7

Hint

Take the values from the standard normal distribution table or chart

8

Step

P(Z>1)

1 - 0.8413

9

Step

P(Z>1)

0.1587

10

Step

Probability that a car picked at random is travelling at more than 100 km/hr

0.1587

11

Answer

C

Tutor: Questions

Seq Type Question Audio

1

Problem

What did you learn from this problem?

2

Clue

What did you learn from the clues?

3

Hint

What did you learn from the Hints?

4

Step

What did you learn from the Steps?

5

Step

How can we improve the Steps?


Copyright © 2020-2022 saibook.us Contact: info@saibook.us Version: 1.5 Built: 27-February-2023 06:00 AM EST