Step-by-step explanation:
See image
An equation is formed of two equal expressions. The value of x is 3.23.
An equation is formed when two equal expressions are equated together with the help of an equal sign '='.
The cost of x cans can be written as
The cost of (x+4) cans can be written as,
Now, the total cost of the cans is given to us like $3.35, therefore, the value of x can be written as,
Hence, the value of x is 3.23.
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Answer:
:) /
Step-by-step explanation:,,
Answer:
The answer is B:subtract 1,add x,divide by 4
The other answer is D:add x,subtract 1,divide 4
Step-by-step explanation:
when you subtract 1 you isolate 3x so the equation looks like 3x=-x+3
the next step is to add x to both sides so you isolate the x to one side after doing that your equation should look like 4x=3,after this you divide both sides to the solution x=
The answer is also D because if you add x to both sides u isolate x to the left side so the equation will look like 1+4x=4 the next step will be to subtract one from each side and after doing this the equation should look like 4x=3 which should look familiar because its the same exact solution as B was so the answer to this choice is x=
With that evidence I can reasonably say that answer to the question is B,and D
4x+3y=37
y=x-4
b. Create a vector x by generating n=50 numbers from N(mean=30,sd=2) distribution. Calculate the confidence interval from this data using the CI formula. Check whether the interval covers the true mean=30 or not.
c. Repeat the above experiments for 200 times to obtain 200 such intervals. Calculate the percentage of intervals that cover the true mean=30. This is the empirical coverage probability. In theory, it should be very close to your CL.
d. Write a function using CL as an input argument, and the percentage calculated from question c as an output. Use this function to create a 5 by 2 matrix with one column showing the theoretical CL and the other showing the empirical coverage probability, for CL=.8, .85, .9, .95,.99.
a. To find the z score for a given confidence level, you can use the `qnorm()` function in R. The `qnorm()` function takes a probability as an argument and returns the corresponding z score. To find the z score for a 95% confidence level, you can use `qnorm(1-.025)`:
```R
z <- qnorm(1-.025)
```
This will give you the z score for a 95% confidence level, which is approximately 1.96.
b. To create a vector `x` with 50 numbers from a normal distribution with mean 30 and standard deviation 2, you can use the `rnorm()` function:
```R
x <- rnorm(50, mean = 30, sd = 2)
```
To calculate the confidence interval for this data, you can use the formula:
```R
CI <- mean(x) + c(-1, 1) * z * sd(x) / sqrt(length(x))
```
This will give you the lower and upper bounds of the 95% confidence interval. You can check whether the interval covers the true mean of 30 by seeing if 30 is between the lower and upper bounds:
```R
lower <- CI[1]
upper <- CI[2]
if (lower <= 30 && upper >= 30) {
print("The interval covers the true mean.")
} else {
print("The interval does not cover the true mean.")
}
```
c. To repeat the above experiment 200 times and calculate the percentage of intervals that cover the true mean, you can use a for loop:
```R
count <- 0
for (i in 1:200) {
x <- rnorm(50, mean = 30, sd = 2)
CI <- mean(x) + c(-1, 1) * z * sd(x) / sqrt(length(x))
lower <- CI[1]
upper <- CI[2]
if (lower <= 30 && upper >= 30) {
count <- count + 1
}
}
percentage <- count / 200
```
This will give you the percentage of intervals that cover the true mean.
d. To write a function that takes a confidence level as an input and returns the percentage of intervals that cover the true mean, you can use the following code:
```R
calculate_percentage <- function(CL) {
z <- qnorm(1-(1-CL)/2)
count <- 0
for (i in 1:200) {
x <- rnorm(50, mean = 30, sd = 2)
CI <- mean(x) + c(-1, 1) * z * sd(x) / sqrt(length(x))
lower <- CI[1]
upper <- CI[2]
if (lower <= 30 && upper >= 30) {
count <- count + 1
}
}
percentage <- count / 200
return(percentage)
}
```
You can then use this function to create a 5 by 2 matrix with one column showing the theoretical CL and the other showing the empirical coverage probability:
```R
CL <- c(.8, .85, .9, .95, .99)
percentage <- sapply(CL, calculate_percentage)
matrix <- cbind(CL, percentage)
```
This will give you a matrix with the theoretical CL in the first column and the empirical coverage probability in the second column.
Know more about z score here:
#SPJ11
Answer:
-16
Step-by-step explanation:
We are given that a function
We have to find the value of given function at x=2
To find the value of function at x=2 we will substitute x=2 in given function.
Substitute x=2 in given function
Then, we get
Using multiplication property of integer
Subtraction property of integers
Hence, the value of function at x=2 =-16