The ratio 20mins to 1 hour can be written in the form 1:n find the value of n.

A population has a mean of 200 and a standard deviation of 50. Suppose a sample of size 100 is selected and x is used to estimat

zmey [24]

Answer:

a) 0.6426 = 64.26% probability that the sample mean will be within +/- 5 of the population mean.

b) 0.9544 = 95.44% probability that the sample mean will be within +/- 10 of the population mean.

Step-by-step explanation:

To solve this question, we need to understand the normal probability distribution and the central limit theorem.

Normal probability distribution

When the distribution is normal, we use 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.

Central Limit Theorem

The Central Limit Theorem estabilishes that, for a normally distributed random variable X, with mean $\mu$ and standard deviation $\sigma$ , the sampling distribution of the sample means with size n can be approximated to a normal distribution with mean $\mu$ and standard deviation $s = \frac{\sigma}{\sqrt{n}}$ .

For a skewed variable, the Central Limit Theorem can also be applied, as long as n is at least 30.

In this question, we have that:

$\mu = 200, \sigma = 50, n = 100, s = \frac{50}{\sqrt{100}} = 5$

a. What is the probability that the sample mean will be within +/- 5 of the population mean (to 4 decimals)?

This is the pvalue of Z when X = 200 + 5 = 205 subtracted by the pvalue of Z when X = 200 - 5 = 195.

Due to the Central Limit Theorem, Z is:

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

X = 205

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

$Z = \frac{205 - 200}{5}$

$Z = 1$

$Z = 1$ has a pvalue of 0.8413.

X = 195

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

$Z = \frac{195 - 200}{5}$

$Z = -1$

$Z = -1$ has a pvalue of 0.1587.

0.8413 - 0.1587 = 0.6426

0.6426 = 64.26% probability that the sample mean will be within +/- 5 of the population mean.

b. What is the probability that the sample mean will be within +/- 10 of the population mean (to 4 decimals)?

This is the pvalue of Z when X = 210 subtracted by the pvalue of Z when X = 190.

X = 210

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

$Z = \frac{210 - 200}{5}$

$Z = 2$

$Z = 2$ has a pvalue of 0.9772.

X = 195

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

$Z = \frac{190 - 200}{5}$

$Z = -2$

$Z = -2$ has a pvalue of 0.0228.

0.9772 - 0.0228 = 0.9544

0.9544 = 95.44% probability that the sample mean will be within +/- 10 of the population mean.

7 0

2 years ago

Measurements of atoms, such as amounts, distances, and weights, are often very large or very small when compared to measurements

Ainat [17]

Answer:

Step-by-step explanation:

1)3.8 *10¹⁵

2)4.0*10¹⁴

3)30.4*10⁻²⁰

4)523,000,000,000 atoms

5)0.000 000 000 000 000 000 000 000 00167

7 0

2 years ago

David uses 1/2 cup of apple juice for every 1/4 cup of cranberry juice to make a fruit drink. Find out the number of cups of app

statuscvo [17]

Well, he would use 4/4 cup of cranberry juice to equal 1 cup. that is 4x the original amount. so, multiply 1/2 × 4 to equal 2 cups. David would use 2 cups of apple juice for every 1 cup of cranberry juice.

5 0

3 years ago

If a cup of coffee is at 90°C and a person with a body temperature of 36°C touches it, how will heat flow between them?

Alex777 [14]

Answer:

The answer is B (From the cup to the hand)

Step-by-step explanation:

5 0

3 years ago

Read 2 more answers

What is the order, from narrowest to widest graph, of the quadratic functions f (x) = -10x2, f (x) = 2x2, and f (x) = 0.5x2?

Varvara68 [4.7K]

The <em>correct answer</em> is:

f(x) = -10x², f(x) = 2x², and f(x) = 0.5x²

Explanation:

For a quadratic in standard form, f(x) = ax²+bx+c, the value of a describes the width and direction of the parabola. If a is positive, the parabola is open upward. If a is negative, the parabola is open downward.

If a < 1, a fraction or decimal, the graph is wider than the parent function f(x)=x². If a > 1, the graph is narrower than the parent function f(x)=x². The larger the value of a is (a > 1), the narrower the graph is. This makes the function with the decimal value of a the widest; the remaining graphs are in order of the value of a, least to greatest.

3 0

2 years ago

Read 2 more answers