Sarah bought 7 more songs than Betsy.If Sarah bought 21 songs from Apple Music, how many songs did Betsy buy?

-7(a - 3) = 11 - 7a<br> what’s the answer

natali 33 [55]

Answer:

the statement is false there is no solution

Step-by-step explanation:

step 1 -7(a-3)=11-7a

step 2 -7a+21=11-7a

step 3 cancel out the -7a's

step 4 you are left with 21=11 which does not work so it is false

8 0

3 years ago

Researchers are interested in the effect of a certain nutrient on the growth rate of plant seedlings. Using a hydroponics grow p

Ede4ka [16]

Answer:

1) The mean calculated for this case is $\bar X=61.5$

2) $61.5-5.4=56.1$

3) $61.5+5.4=66.9$

4) B. An interval estimate gives us a sense of the accuracy of the point estimate whereas a point estimate alone does not.

Because with the confidence interval we know the confidence level of the interval, and the limits for the parameter at some significance level.

Step-by-step explanation:

Previous concepts

A confidence interval is "a range of values that’s likely to include a population value with a certain degree of confidence. It is often expressed a % whereby a population means lies between an upper and lower interval".

The margin of error is the range of values below and above the sample statistic in a confidence interval.

Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".

Part 1

In order to calculate the mean and the sample deviation we can use the following formulas:

$\bar X= \sum_{i=1}^n \frac{x_i}{n}$ (a)