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3 years ago

Add using a number line. −0.5 + (−1.7)

Mathematics

2 answers:

Alik [6]3 years ago

4 0

Answer: -2.2 your welcome

Step-by-step explanation:

stira [4]3 years ago

3 0

-2.2 is the answer simplified by the expression

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The height of a cone-shaped container is 18 centimeters and its radius is 7 centimeters. Meg fills the container completely with

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3 years ago

Suppose T= {-8,-4,0,4,8,12,16,20} and K= {-3,-2,-1,0,1,2,3,4,5,6}. What is T U K?

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3 years ago

There are 5280 feet in a mile. How many miles 2) A recipe needs 4 cups of milk. A cup is 8 ounces.

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3 years ago

A consumer group has determined that the distribution of life spans for gas ovens has a mean of 15.0 years and a standard deviat

Mnenie [13.5K]

Answer:

B. Mean = 1.6 years, standard deviation = 0.92 years, shape: approximately Normal.

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 normal distributions can be 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.

Subtraction of normal variables:

When we subtract normal variables, the mean is the subtraction of the means, while the standard deviation is the square root of the sum of the variances.

35 gas ovens

A consumer group has determined that the distribution of life spans for gas ovens has a mean of 15.0 years and a standard deviation of 4.2 years. This means that:

$\mu_G = 15, \sigma_G = 4.2, n = 35, s_G = \frac{4.2}{\sqrt{35}} = 0.71$

40 electric ovens.

The distribution of life spans for electric ovens has a mean of 13.4 years and a standard deviation of 3.7 years.

$\mu_E = 13.4, \sigma_E = 3.7, n = 40, s_E = \frac{3.7}{\sqrt{40}} = 0.585$

Which of the following best describes the sampling distribution of barXG - bar XE, the difference in mean life span of gas and electric ovens?

By the Central Limit Theorem, the shape is approximately normal.

Mean: $\mu = \mu_G - \mu_E = 15 - 13.4 = 1.6$

Standard deviation:

$s = \sqrt{s_G^2+s_E^2} = \sqrt{(0.71)^2+(0.585)^2} = 0.92$

So the correct answer is given by option b.

3 0

3 years ago

The Miller family visited Mama's Kitchen and ordered 4 hamburgers and 3 medium fries and paid $13.27. James ordered a medium dri

ioda

Let's start out by setting up three separate equations for each customer.
d = cost of drink, f = cost of fries, h = cost of hamburger

Miller Family: 4h + 3f = 13.27
James: d + h + 2f = 6.33
Steven: 2h + f + d = 7.04

Since the Miller's didn't order any drinks, let's start by using substitution to find the cost of d between James and Steven.

Let's isolate d with James:
d + h + 2f = 6.33
d = 6.33 - h - 2f

Now let's plug that into Steven's equation:
2h + f + d = 7.04
2h + f + (6.33 - h - 2f) = 7.04
h - f + 6.33 = 7.04
h - f = 0.71
h = 0.71 + f

Let's plug that new h into the Miller Family's equation:
4h + 3f = 13.27
4(0.71 + f) + 3f = 13.27
2.84 + 4f + 3f = 13.27
2.84 + 7f = 13.27
7f = 10.43
f = 1.49

So medium fries cost $1.49

Let's plug f back into the Miller Family's equation to get h:
4h + 3f = 13.27
4h + 3(1.49) = 13.27
4h + 4.47 = 13.27
4h = 8.8
h = 2.2

So a hamburger costs $2.20

Let's plug h and f into Steven's equation to calculate d

2h + f + d = 7.04
2(2.2) + (1.49) + d = 7.04
4.4 + 1.49 + d = 7.04
5.89 + d = 7.04
d = 1.15

So a medium drink costs $1.15

The answer is B. Drink = $1.15, Fries = $1.49, Hamburger = $2.20

5 0

3 years ago

Add using a number line. ​ −0.5 + (−1.7) ​

Add using a number line. −0.5 + (−1.7)