Karen and Ann share the cost of a DVD that costs $29.90

nydimaria [60]

Answer:

29 nickels, 12 dimes

If the number of nickels is 7 less than three times the number of dimes, the answers should be 29 nickels and 12 dimes. Hope it helps!

7 0

2 years ago

Read 2 more answers

In the 2014 - 2015 school year, the mean score on the critical reading of the SAT was 490 with a standard deviation of 102 for j

bonufazy [111]

Answer:

The Ranking Percentile is (B) 97.5%

Explanation :

To find the percentile rank we need to find the z- score. After finding the z-score match this value with the corresponding value in z-score table.

Formula to find the z-score

Z-score= $\frac{\text { scored obtained - mean }(\mu)}{\text { standard deviation }(\sigma)}$

Substituting the values in the above equation, we find

Z-score= $\frac{(694-490)}{102}$ =2

So, the Z-score is +2

Now, the corresponding value of Z-score 2 in the table is 0.9772

or the percentile score is 97.72 ~ 97.5 .

3 0

2 years ago

A simple random sample of size nequals10 is obtained from a population with muequals68 and sigmaequals15. (a) What must be true

valentina_108 [34]

Answer:

(a) The distribution of the sample mean ( $\bar x$ ) is N (68, 4.74²).

(b) The value of $P(\bar X$ is 0.7642.

(c) The value of $P(\bar X\geq 69.1)$ is 0.3670.

Step-by-step explanation:

A random sample of size n = 10 is selected from a population.

Let the population be made up of the random variable X.

The mean and standard deviation of X are:

$\mu=68\\\sigma=15$

(a)

According to the Central Limit Theorem if we have a population with mean μ and standard deviation σ and we take appropriately huge random samples (n ≥ 30) from the population with replacement, then the distribution of the sample mean will be approximately normally distributed.

Since the sample selected is not large, i.e. n = 10 < 30, for the distribution of the sample mean will be approximately normally distributed, the population from which the sample is selected must be normally distributed.

Then, the mean of the distribution of the sample mean is given by,

$\mu_{\bar x}=\mu=68$