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pickupchik [31]

3 years ago

13

which expression correctly shows the commutative proberty? a)8+14+22+9=(8+14)+(22+9). b)8+14+22+9=8+(14+22)+9. c)8+14+22+9=53. d

)8+14+22+9=8+22+14+9

1 answer:

Lerok [7]3 years ago

5 0

D has the commutative property because it just flip flopped the numbers.

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Why are quartiles generally more reliable for judging outliers than mean and standard deviation?

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In a regular 52 deck of cards, what is the probability of picking a random spade, a 4 of any suit and then a random diamond with

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1 year ago

1.) Some banks charge a fee on savings accounts that are left inactive for an extended period of time. The equation y = 5000 * (

oee [108]

Answer:

a. The initial amount of money that was left in this savings account was of 5000.

b. Decrease of 2% each year.

Step-by-step explanation:

Exponential function:

An exponential function, with an initial value of A(0), and a decay rate of r, as a decimal, is given by:

$A(t) = A(0)(1-r)^t$

In this question, we have:

$y = 5000*(0.98)^x$

a. What was the initial amount of money that was left in this savings account?

This is y(0) = 5000

The initial amount of money that was left in this savings account was of 5000.

b. What is the percent of change each year in this savings account?

First as a decimal.

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r = 1 - 0.98

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2 years ago

The shape of the distribution of the time required to get an oil change at a 20 minute oil change facility. However, records ind

Katyanochek1 [597]

Answer:

For a mean oil change time of 20.51 minutes there would be a 10% chance of being at or below

Step-by-step explanation:

To solve this question, we need to understand the normal probability distribution and the central limit theorem.

Normal probability distribution

Problems of normally distributed samples are solved using the z-score formula.

In a set with mean $\mu$ and standard deviation $\sigma$ , the zscore of a measure X is given by:

$Z = \frac{X - \mu}{\sigma}$

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.

Central Limit Theorem

The Central Limit Theorem estabilishes that, for a normally distributed random variable X, with mean $\mu$ and standard deviation $\sigma$ , the sampling distribution of the sample means with size n can be approximated to a normal distribution with mean $\mu$ and standard deviation $s = \frac{\sigma}{\sqrt{n}}$ .

For a skewed variable, the Central Limit Theorem can also be applied, as long as n is at least 30.

In this problem, we have that:

$\mu = 21.3, \sigma = 3.9, n = 40, s = \frac{3.9}{\sqrt{40}} = 0.6166$

Treating this as a random sample, at what mean oil-change time would there be a 10% chance of being at or below?

This is the 10th percentile, which is X when Z has a pvalue of 0.1. So it is X when Z = -1.28.

$Z = \frac{X - \mu}{\sigma}$

By the Central Limit Theorem

$Z = \frac{X - \mu}{s}$

$-1.28 = \frac{X - 21.3}{0.6166}$

$X - 21.3 = -1.28*0.6166$

$X = 20.51$

For a mean oil change time of 20.51 minutes there would be a 10% chance of being at or below

6 0

3 years ago