2.2a+3.4b=1.2a+2.6 solve for a

One sample z-test is performed if the sample size is large enough (n > 30) and we want to know if the sample comes from the specific population.

For this case, we're specified that:

Population mean = $\mu$ = $150
Population standard deviation = $\sigma$ = $30.20
Sample mean = $\overline{x}$ = $160
Sample size = n = 40 > 30
Level of significance = $\alpha$ = 2.5% = 0.025
We want to determine if the average customer spends more in his store than the national average.

Forming hypotheses:

Null Hypothesis: Nullifies what we're trying to determine. Assumes that the average customer doesn't spend more in the store than the national average. Symbolically, we get: $H_0: \mu_0 \leq \mu = 150$
Alternate hypothesis: Assumes that customer spends more in his store than the national average. Symbolically $H_1: \mu_0 > \mu = 150$

where $\mu_0$ is the hypothesized population mean of the money his customer spends in his store.

The z-test statistic we get is:

$z = \dfrac{\overline{x} - \mu_0}{\sigma/\sqrt{n}} = \dfrac{160 - 150}{30.20/\sqrt{40}} \approx 2.094$

The test is single tailed, (right tailed).

The critical value of z at level of significance 0.025 is 1.96

Since we've got 2.904 > 1.96, so we reject the null hypothesis.

(as for right tailed test, we reject null hypothesis if the test statistic is > critical value).

Thus, we accept the alternate hypothesis that customer spends more in his store than the national average.

Learn more about one-sample z-test here:

brainly.com/question/21477856

3 0

1 year ago

Read 2 more answers

Find the measure of the arc or angle indicated

MariettaO [177]

Short Answer: arc LM = 110°
Comment
Any two angles that have their end points on the same end points as a chord and both moving away in the same direction (in this case down ) are equal. This is a fundamental fact about circles.

Equation
2x + 55 = x + 55
the only way this is going to make any sense is if x = 0. No other value is possible because it will destroy the equality.

Conclusion
Both angles = 55

But that's not what you are asked for.

What you are asked for
You want to know the measure of arc LM.
The angle connecting the center of the circle with its two arms running through the end points of the chord = the measure of arc LM

Draw a dot where the center of the circle is and call it O. Draw in <MOL
<MOL = 2* either of the 55° = 2 (<LKM) = 2 * 55 = 110° That's a property of the central angle.

The measure of arc LM = 110°

6 0

2 years ago

OPTIONS:

kondor19780726 [428]

You have to combine like terms (terms that have the same variable(x,y....) and power/exponent)²³

(4x³ - 4 + 7x) - (2x³ - x - 8) Distribute -1 into (2x³ - x - 8)

(4x³ - 4 + 7x) + (-)2x³ - (-)x - (-)8 (two negative signs cancel each other out and become positive)

(4x³ - 4 + 7x) - 2x³ + x + 8 Now combine like terms

4x³ - 2x³ + 7x + x - 4 + 8 (I rearranged for the like terms to be next to each other)

2x³ + 8x + 4 It is equivalent to B

$(-3x^2+x^4+x)+(2x^4-7+4x)$ Combine like terms

$-3x^2+x^4+2x^4+x+4x-7$ (I rearranged for the like terms to be next to each other)

$-3x^2+3x^4+5x-7$ It is equivalent to D

(x² - 2x)(2x + 3) Distribute x² into (2x + 3) and distribute -2x into (2x + 3)

(x²)2x + (x²)3 + (-2x)2x + (-2x)3

When you multiply a variable with an exponent by a variable with an exponent, you add the exponents together

2x³ + 3x² - 4x² - 6x Combine like terms

2x³ - x² - 6x It is equivalent to A

[Info]

When you multiply a variable with an exponent by a variable with an exponent, you add the exponents together. (You can combine the exponents only if they have the same variable)

For example:

$x^{2} (x^3)=x^{(2+3)}=x^5$

$(y^3)x^2=y^3x^2$ (You can't combine them because they have different exponents of y and x)

$(5^2)(5^4)=5^{(2+4)}=5^6=15,625$

7 0

2 years ago