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2 years ago

Aaron's car used 3- gallons of gas when

2 answers:

monitta2 years ago

4 0

We want to find miles per gallon. Another way of saying miles per gallon is miles/gallon. So we will plug the numbers into this equation:

60 miles/3 gallons = 20 miles/gallon

This is because 60/3=20.

I hope this makes sense.

skad [1K]2 years ago

4 0

Answer:

His car gets 20 miles per gallon.

Step-by-step explanation:

1. 60 = 3x (divide by 3)

2. 20 = x

Therefore, the car uses 20 miles per gallon.

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What answer choice is it?

Alinara [238K]

Answer:

I am pretty sure it is A

Step-by-step explanation:

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2 years ago

Convert the following to Standard Form: (x - 5)^2 + 4

netineya [11]

Answer:

x² - 10x + 29

Step-by-step explanation:

The standard form of a quadratic is , ax² + bx + c (a ≠ 0 )

Given

(x - 5)² + 4 ← expand factor using FOIL

= x² - 10x + 25 + 4

= x² - 10x + 29 ← in standard form

5 0

2 years ago

A random sample of 20 students yielded a mean of ¯x = 72 and a variance of s2 = 16 for scores on a college placement test in mat

Helen [10]

Answer:

The 98% confidence interval for the variance in the pounds of impurities would be $8.400 \leq \sigma^2 \leq 39.827$ .

Step-by-step explanation:

1) Data given and notation

$s^2 =16$ represent the sample variance

s=4 represent the sample standard deviation

$\bar x$ represent the sample mean

n=20 the sample size

Confidence=98% or 0.98

A confidence interval is "a range of values that’s likely to include a population value with a certain degree of confidence. It is often expressed a % whereby a population mean or variance lies between an upper and lower interval".

The margin of error is the range of values below and above the sample statistic in a confidence interval.

The Chi square distribution is the distribution of the sum of squared standard normal deviates .

2) Calculating the confidence interval

The confidence interval for the population variance is given by the following formula:

$\frac{(n-1)s^2}{\chi^2_{\alpha/2}} \leq \sigma^2 \leq \frac{(n-1)s^2}{\chi^2_{1-\alpha/2}}$

On this case the sample variance is given and for the sample deviation is just the square root of the sample variance.

The next step would be calculate the critical values. First we need to calculate the degrees of freedom given by:

$df=n-1=20-1=19$

Since the Confidence is 0.98 or 98%, the value of $\alpha=0.02$ and $\alpha/2 =0.01$ , and we can use excel, a calculator or a table to find the critical values.