A confidence interval for a mean "gives us a range of plausible values for the population mean. If a confidence interval does not include a particular value, we can say that it is not likely that the particular value is the true population mean"

$s=16.6$ represent the sample deviation

$\bar X=12.8$ represent the sample mean

n =1003 is the sample size selected

Confidence =99% or 0.99

$\alpha=1-0.99=0.01$ represent the significance level.

2) Solution to the problem

The confidence interval for the mean would be given by this formula

$\bar X \pm z_{\alpha/2} \frac{s}{\sqrt{n}}$

We can use a z quantile instead of t since the sample size is large enough.

For the 99% confidence interval the value of $\alpha=1-0.99=0.01$ and $\alpha/2=0.005$ , with that value we can find the quantile required for the interval in the normal standard distribution.

$z_{\alpha/2}=2.58$

And replacing into the confidence interval formula we got:

$12.8 - 2.58 \frac{16.6}{\sqrt{1003}}=11.448$

$12.8 + 2.58 \frac{16.6}{\sqrt{1003}} =14.152$

And the 99% confidence interval would be given (11.448;14.152).

We are confident that about 11 to 14 are the number of books that the people had read on the last year on average, at 1% of significance.

3 0

3 years ago

Annies car used 100 cups of gasoline during a drive he paid $3.12 per gallon for gas. how much did the gas cost ?

VladimirAG [237]

The gas would have cost $19.50. Hope this helps :)

5 0

2 years ago

Read 2 more answers

If Radhika adds these two numbers and represents the sum on an abacus, and if the beads on the ten's place are 2 and the beads o

xxTIMURxx [149]

Answer:

Explained below.

Step-by-step explanation:

A standard abacus is a traditional method used to perform basic mathematical calculations, such as addition, subtraction, multiplication and division.

There are 5 rods on a standard abacus.

The shape of the abacus has a series of vertical rods on which a number of beads are placed.

Each bead on a particular rod is considered as 1 unit, i.e. if there are three beads on a rod, the value of that rod is 3.

The last rod on an abacus is for the unit's place, the second last rod is for the ten's place, the third last rod is for the hundredth's place, the fourth last rod is for the thousandth's place and the fifth rod is for the ten thousandth's place.

8 0

3 years ago