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3 years ago

What is this 5a+2b-3a+4

Mathematics

1 answer:

seropon [69]3 years ago

4 0

Answer:

8a+2b+4

Step-by-step explanation:

combine all like terms

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The scores of high school seniors on the act college entrance examination in a recent year had mean Î¼ = 20.8 and standard devia

natka813 [3]

To solve this problem, we make use of the z statistic. The formula for z score is:

z = (x – μ) / s

where,

x = is the sample score = 21 or higher

μ = the population mean = 20.8

s = the standard deviation = 4.8

Solving for the z score:

z = (21 – 20.8) / 4.8

z = 0.0417

Next step to do is to find for the p value using the standard distribution tables at z = 0.04. Since we are looking for the probability of getting 21 or higher, therefore this is a right tailed test, hence

p = 0.516

So there is about 51.6% that a student will get a score of 21 or greater.

4 0

3 years ago

A researcher compares the effectiveness of two different instructional methods for teaching electronics. A sample of 138 student

yan [13]

Answer:

The 98% confidence interval for the true difference between testing averages for students using Method 1 and students using Method 2 is (-8.04, 0.84).

Step-by-step explanation:

The (1 - α)% confidence interval for the difference between population means is:

$CI=(\bar x_{1}-\bar x_{2})\pm z_{\alpha/2}\times \sqrt{\frac{\sigma^{2}_{1}}{n_{1}}+\frac{\sigma^{2}_{2}}{n_{2}}}$

The information provided is as follows:

$n_{1}= 138\\n_{2}=156\\\bar x_{1}=61\\\bar x_{2}=64.6\\\sigma_{1}=18.53\\\sigma_{2}=13.43$

The critical value of z for 98% confidence level is,

$z_{\alpha/2}=z_{0.02/2}=2.326$

Compute the 98% confidence interval for the true difference between testing averages for students using Method 1 and students using Method 2 as follows:

$CI=(\bar x_{1}-\bar x_{2})\pm z_{\alpha/2}\times \sqrt{\frac{\sigma^{2}_{1}}{n_{1}}+\frac{\sigma^{2}_{2}}{n_{2}}}$

$=(61-64.6)\pm 2.326\times\sqrt{\frac{(18.53)^{2}}{138}+\frac{(13.43)^{2}}{156}}\\\\=-3.6\pm 4.4404\\\\=(-8.0404, 0.8404)\\\\\approx (-8.04, 0.84)$

Thus, the 98% confidence interval for the true difference between testing averages for students using Method 1 and students using Method 2 is (-8.04, 0.84).

5 0

3 years ago

Carl and Rita ate breakfast at the local diner. Their bill came to $11.48. They gave their waitress a tip that was 25% of the bi

Trava [24]

Converting percentage to a decimal:
25% = 25 / 100 = 0.25 

What is 25% of 11.48 
= 25% * 11.48 
= 0.25 * 11.48 
= 2.87

5 0

4 years ago

58 yd 73 yd Use 3.14 Instead Of Pie Symbol

defon

Answer:

$771096.8 \: yd^{3}$

Step-by-step explanation:

If you are trying to find the volume, you would use the formula:

$\pi \: r ^{2} (h)$

You would plug in the radius (r), which is 58, and then plug in the height, which is 73.

Make sure you remember to use 3.14 and not the pi key if you are using a calculator.

The final answer is 771,096.8 yd^3

7 0

4 years ago

How can you determine if two triangle angles are similar using their angle measurements???? In ur own words !!

Andrej [43]

Answer:

If two pairs of corresponding angles in a pair of triangles are congruent, then the triangles are similar. We know this because if two angle pairs are the same, then the third pair must also be equal. When the three angle pairs are all equal, the three pairs of sides must also be in proportion.

Step-by-step explanation:

hope this helps:0

4 0

3 years ago