60+42.95x=25+49.95x value for x

PLS HELP 55 POINTS PLSS NO LINKS PLS HELPP

Semenov [28]

Answer:

12. 114 Laps

13. 234 students don't ride the bus.

14. 1.5% of 26,500.60 is 397.50 so the answer is $26,500.60

15. 24% × 63.4 = 15.2 so the original weight of the bag is 63.4 pounds

Step-by-step explanation:

4 0

2 years ago

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

3 years ago

The difference between one-fifth of a number and 4 is -75

Varvara68 [4.7K]

Think of this as (1/5)x - 4 = -75, where x is the number that we are trying to figure out. To figure this out, we want to get x by itself, so we can go:

(1/5)x=-71
x=-71*5
x=-355

So your number is -355

7 0

3 years ago

1.) The check number on a check:

ziro4ka [17]

Answer:

D) Identifies the transaction and is located at the top right corner of the check

Step-by-step explanation:

The check number on a check is the number located at the top right corner of the check, and it can also be found at the bottom of the check, located in lower right corner after the routing number and the account number

The check number aids in the tracking and identifying bank transactions such as to identify checks that the bank has processed and to know outstanding checks that are yet to be processed.

The check number also aids in balancing of the checkbook.

Therefore, the check number on a check identifies the transactions and is located at the top right corner of the check.

4 0

2 years ago

for a project in her geometry class, amira uses a mirror on the ground to measure the height of her school’s football goalpost.

kari74 [83]

Answer:

6.14 m

Step-by-step explanation:

8 0

3 years ago