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3 years ago

A stereo is marked down $105. if this is a 25% decrease, find the cost price?

Mathematics

1 answer:

Aneli [31]3 years ago

3 0

Answer:420$
Solution: 105•4= 420$
25%= 1/4 therefore we can find the original price by multiplying the decrease with 4

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You can buy 20 fluid ounces of shampoo for $4.40 or, you can buy 24 fluid ounces for $4.80 which is the better buy? Please answe

erica [24]

Answer: the 20 fluid ounces is better

Step-by-step explanation:

If you divide 20 by 4.40 that is 4.54 but if you divide 24 by 4.80 that is 5. You want to divide 20 by 4.40 because 20 is the fluid ounces and 4.40 is the money divide that to get the cost per fluid ounce then you do the same with the 24 fluid ounces and by doing that you get the sot for 1 fluid ounce then look at both of your answers and see which one is less. which one is less is the better one.

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3 years ago

Read 2 more answers

Find the slope of the line through each pair of points. (15, 8), (-1, 15).

Natalija [7]

Answer:

22.6

Step-by-step explanation:

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3 years ago

The sales tax for a certain state can be found by multiplying the purchase price by . What is the sales tax on an item that is $

Tamiku [17]

Ok any more details or is that the question?

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2 years ago

a math teacher claims that she has developed a review course that increases the score of students on the math portion of a colle

madam [21]

Answer:

$H_0: \mu\leq514\\\\H_1: \mu>514$

B. Z=2.255. P=0.01207.

C. Although it is not big difference, it is an improvement that has evidence. The scores are expected to be higher in average than without the review course.

D. P(z>0.94)=0.1736

Step-by-step explanation:

<em>A. state the null and alternative hypotheses.</em>

The null hypothesis states that the review course has no effect, so the scores are still the same. The alternative hypothesis states that the review course increase the score.

$H_0: \mu\leq514\\\\H_1: \mu>514$

B. test the hypothesis at the a=.10 level of confidence. is a mean math score of 520 significantly higher than 514? find the test statistic, find P-value. is the sample statistic significantly higher?

The test statistic Z can be calculated as

$Z=\frac{M-\mu}{s/\sqrt{N}} =\frac{520-514}{119/\sqrt{2000}}=\frac{6}{2.661}=2.255$

The P-value of z=2.255 is P=0.01207.

The P-value is smaller than the significance level, so the effect is significant. The null hypothesis is rejected.

Then we can conclude that the score of 520 is significantly higher than 514, in this case, specially because the big sample size.

C. do you think that a mean math score of 520 vs 514 will affect the decision of a school admissions adminstrator? in other words does the increase in the score have any practical significance?

Although it is not big difference, it is an improvement that has evidence. The scores are expected to be higher in average than without the review course.

D. test the hypothesis at the a=.10 level of confidence with n=350 students. assume that the sample mean is still 520 and the sample standard deviation is still 119. is a sample mean of 520 significantly more than 514? find test statistic, find p value, is the sample mean statisically significantly higher? what do you conclude about the impact of large samples on the p-value?

In this case, the z-value is

$Z=\frac{520-514}{s/\sqrt{n}} =\frac{6}{119/\sqrt{350}} =\frac{6}{6.36} =0.94\\\\P(z>0.94)=0.1736>\alpha$

In this case, the P-value is greater than the significance level, so there is no evidence that the review course is increasing the scores.

The sample size gives robustness to the results of the sample. A large sample is more representative of the population than a smaller sample. A little difference, as 520 from 514, but in a big sample leads to a more strong evidence of a change in the mean score.

Large samples give more extreme values of z, so P-values that are smaller and therefore tend to be smaller than the significance level.

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2 years ago