Which of these is an example of a random sample?

2 answers:

7 0

"<span>D.A phone survey is conducted using twenty names randomly taken from the phone book" is the only example of a random sample. All the others take into account the environment. </span>

Lynna [10]4 years ago

3 0

Answer:

D.) A phone survey is conducted using twenty names randomly taken from the phone book.

Step-by-step explanation:

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How much hotdogs can parker eat in an hour???

sweet-ann [11.9K]

Answer:

I don't know because there is no info for the question but the record for most hotdogs eaten is 74 hotdogs if that helps.

6 0

3 years ago

Find the 9th partial sum of the geometric sequence an=43n–1.

siniylev [52]

Answer:

39364.

Step-by-step explanation:

I guess its an = 4*(3)^(n-1)

r = 3, a1 = 4 and n = 9

Sum of n terms = a1 * (r^n - 1) / (r - 1)

so S9 = 4 *(3^9 - 1) / (3 - 1)

= 4 * (19683 - 1) / 2

= 78728/2

= 39364.

7 0

3 years ago

An appliance dealer's website features the mean life expectancy values for major household appliances. A standard refrigerator's

marshall27 [118]

Answer:

There is an 84% probability that your standard refrigerator will last between 12 and 20 years.

Step-by-step explanation:

Problems of normally distributed samples can be solved using the z-score formula.

In a set with mean $\mu$ and standard deviation $\sigma$ , the zscore of a measure X is given by:

$Z = \frac{X - \mu}{\sigma}$

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.

In this problem, we have that:

A standard refrigerator's mean life expectancy is 18 years with a standard deviation of 2 years. This means that $\mu = 18, \sigma = 2$ .