(please help i need this asap)

Mathematics

1 answer:

iogann1982 [59]3 years ago

7 0

Y=18x I think but don’t just trust me

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Suppose that a wall is constructed from concrete blocks where a block is a normal random variable with mean 11 kg and standard d

Artemon [7]

Answer:

The value for k is about k = 11.093kg.

Step-by-step explanation:

To answer this question, that is, P(x<k) = 0.85, we can use the standardized value for a raw score, or the formula for obtaining z-scores:

$\\ z = \frac{x - \mu}{\sigma}$ [1]

Where

$\\ x$ is the raw score.

$\\ \mu$ is the population mean.

$\\ \sigma$ is the population standard deviation.

In this case, we are asking to find a value x = k, so that 85% of the blocks have weights less than k (kg).

We have also to use the values for the cumulative standard normal distribution with $\\ \mu = 0$ and $\\ \sigma = 1$ to find the value of z that corresponds to a probability of 0.85.

First step: find the z that corresponds to the probability of 0.85.

To use the formula [1], as we previously mentioned, we first need to find the value of z that corresponds to a probability of 0.85 using the cumulative standard normal distribution table (available in any Statistics books or on the Internet). Then, for a cumulative probability of 0.85, the corresponding value for z = 1.03 (approximately).

Second step: solve the formula [1] for x.

Solving this formula for x, we have:

$\\ z = 1.03$