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2 years ago

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The radius of the earth is about 4,000 miles. A) what is the approximate diameter of the earth? b) what is the approximate dista

nce around the earth at the equator?

1 answer:

adoni [48]2 years ago

3 0

A) diameter = radius x 2

Diameter = 4,000 miles x 2 = 8,000 miles

B) distance around the Earth is the circumference.

Circumference = pi x diameter

Circumference = 3.14 x 8,000 = 25,120 miles

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A random sample of 100 people from City A has an average IQ of 120 with a SD of 18. Independently of this, a random sample of 15

Sloan [31]

Answer:

$z=\frac{(120-116)-0}{\sqrt{\frac{18^2}{100}+\frac{15^2}{150}}}}=1.837$

$p_v =P(z>1.837)=1-P(Z$

Comparing the p value with a significance level for example $\alpha=0.05$ we see that $p_v$ so we can conclude that we have enough evidence to reject the null hypothesis, and we can say that the average IQ on city A is signficantly higher than city B at 5% of singificance.

Step-by-step explanation:

$\bar X_{A}=120$ represent the mean for sample 1

$\bar X_{B}=116$ represent the mean for sample 2

$s_{A}=18$ represent the sample standard deviation for 1

$s_{B}=15$ represent the sample standard deviation for 2

$n_{A}=100$ sample size for the group 2

$n_{B}=150$ sample size for the group 2

$\alpha$ Significance level provided

z would represent the statistic (variable of interest)

Concepts and formulas to use

We need to conduct a hypothesis in order to check if residents of City A smarter on average, the system of hypothesis would be:

Null hypothesis: $\mu_{A}-\mu_{B}\leq 0$

Alternative hypothesis: $\mu_{A} - \mu_{B}> 0$

We don't have the population standard deviation's, but the sample sizes are large enough we can apply a z test to compare means, and the statistic is given by:

$z=\frac{(\bar X_{A}-\bar X_{B})-\Delta}{\sqrt{\frac{s^2_{A}}{n_{A}}+\frac{s^2_{B}}{n_{B}}}}$ (1)

z-test: Is used to compare group means. Is one of the most common tests and is used to determine whether the means of two groups are equal to each other.

With the info given we can replace in formula (1) like this:

$z=\frac{(120-116)-0}{\sqrt{\frac{18^2}{100}+\frac{15^2}{150}}}}=1.837$

P value

Since is a one right tailed test the p value would be:

$p_v =P(z>1.837)=1-P(Z$

Comparing the p value with a significance level for example $\alpha=0.05$ we see that $p_v$ so we can conclude that we have enough evidence to reject the null hypothesis, and we can say that the average IQ on city A is signficantly higher than city B at 5% of singificance.

5 0

2 years ago

How Do You Write .0676767 In Scientific Notation?

evablogger [386]

<span>6.8 x 10^-2

The scientific notation of 70, 030, 000. To find the scientific notation of this value </span><span><span>
1.  </span>We first move the period which separates the whole number from the decimal number which is located after the numbers of the given value.</span>
<span><span>2.  </span>We move it in the very recent order number which is seventy million, seven and zero.</span> <span><span>
3.  </span>It becomes 7.003</span>
<span><span>4.  </span>Thus we count how many moves we did from the tens to the ten million order place.</span> <span><span>
5.  </span>7.003 x 10^7<span>
</span></span>

4 0

3 years ago

What is the sum of 1.57 and 6.88? 7 tenths, 3 hundredths, and 5 thousandths 8 ones, 4 tenths, and 5 hundredths 5 ones, 4 tenths,

Alekssandra [29.7K]

Answer:

8 ones, 4 tenths, and 5 hundredths

Step-by-step explanation:

just took the quiz

4 0

3 years ago

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Brandon picked 14 of a pound of cherries. That afternoon, Brandon's brother ate 12 of the cherries. How many pounds of cherries

stellarik [79]

Answer:

2

Step-by-step explanation:

Brandon picked 14 pounds of cherries but later in the afternoon Brandon's brother ate 12 so you would subtracts

14-12 = 2

8 0

3 years ago

If 0.9x-1.3=-3.1, what is the value of x-0.8?

Butoxors [25]

−<span>2.8
</span>Okay so "0.9x-1.3=-3.1" x=-2

<span><span><span>0.9x</span>−1.3</span>=<span>−3.1

</span></span>add 1.3 to both sides

<span><span><span><span>0.9x</span>−1.3</span>+1.3</span>=<span><span>−3.1</span>+1.3

</span></span><span><span>0.9x</span>=<span>−1.8

</span></span>divide both sides by 0.9

<span><span><span>0.9x/</span>0.9</span>=<span><span>−1.8/</span><span>0.9

</span></span></span>x=<span>−2</span>

So if you plug in -2 into "x-0.8" you get −2.8

<span>=<span><span>−2</span>−0.8

</span></span><span>=<span><span>−2-</span><span>0.8

</span></span></span><span>=<span>−2.8

</span></span>Hope this helps.

3 0

3 years ago

Read 2 more answers