Answer:
%35 of them were in color
Step-by-step explanation:
Since 30 percent of the first 200 sold were in color, 200x30/100 = 60 of them were in color.
Since 20 percent of the next 300 sold were in color, 300x20/100 = 60 of them were in color.
Since 90 percent of the last 100 sold were in color, 100x90/100 = 90 of them were in color.
In total, 60 + 60 + 90 = 210 out of 600 were in color.
The percentage is: = → x = = 35
To find the percentage of advertisements that were sold in color, divide the number of color ads by the total number of ads and multiply by 100. We get answer 35.
To find the percentage of advertisements that were sold in color, we need to find the number of color advertisements in each group and then calculate the percentage.
The total number of color ads is 60 + 60 + 90 = 210. To find the percentage, we divide 210 by 600 and multiply by 100.
So, the percentage of advertisements that were in color is 35%.
#SPJ3
a. Based on the reported sample mean and sample standard deviation, explain why it is not reasonable to think that the distribution of volunteer times for the population of South Korean middle school students is approximately normal.
b. The sample size was not given in the paper, but the sample size was described as large. Suppose that the sample size was 500. Explain why it is reasonable to use a one-sample t confidence interval to estimate the population mean even though the population distribution is not approximately normal.
c. Calculate and interpret a confidence interval for the mean number of hours spent in volunteer activities per year for South Korean middle school children.
Answer:
a. If the distribution was normal, many values would be negative, what is incompatible with the response variable (hours dedicated to volunteer activities).
b. If the sample is big, accordingly to the Central Limit Theorem, the sampling distribution shape tends to be normally-like, so we can apply a one-sample t-test.
c. The 95% confidence interval for the mean is (13.307, 16.213).
Step-by-step explanation:
a. If the distribution was normal, the values with one or more standard deviation below the mean would be negative, what is incoherent for this case. This, in a normal distribution, represents approximately 16% of the values.
If we calculate the probabilty for a normal distribution with the sample parameters, the probability of having "negative hours" is 18.6% (see picture attached).
b. If the sample is big, accordingly to the Central Limit Theorem, the sampling distribution shape tends to be normally-like, so we can apply a one-sample t-test.
The sampling distribution standard deviation is also reduced by a factor of 1/√n.
c. We have to calculate a 95% confidence interval for the mean.
The population standard deviation is not known, so we have to estimate it from the sample standard deviation and use a t-students distribution to calculate the critical value.
The sample mean is M=14.76.
The sample size is N=500.
When σ is not known, s divided by the square root of N is used as an estimate of σM:
The t-value for a 95% confidence interval is t=1.965.
The margin of error (MOE) can be calculated as:
Then, the lower and upper bounds of the confidence interval are:
The 95% confidence interval for the mean is (13.307, 16.213).
B. The opposite way the hands move on a clock. (To the left)
Answer:
B. the opposite way the hands move on a clock
Question 18 options:
3x2−4x−4
3x2−2x−4
7x2+4x+3
7x2−4x+2
Answer:
f(x) + g(x) = 7x² - 4x + 2
General Formulas and Concepts:
Algebra I
Step-by-step explanation:
Step 1: Define
f(x) = 5x² - 3x - 1
g(x) = 2x² - x + 3
Step 2: Find f(x) + g(x)
B. x = 1
C. x = -1
D. x = -4
Answer:
D) -4x-1
Step-by-step explanation:
-1(2x+3)-2(x-1)
-2x-3-2x+2
-4x-1
Therefore D is correct
Answer:
Range : [-6, ∞)
Step-by-step explanation:
Domain of any function on a graph is represented by the x-values (input values).
Similarly, Range of function is represented by the y-values or output values of the function on a graph.
Therefore, domain of the given absolute function will be (-∞, ∞) Or set of all real numbers.
Range of the function → [-6, ∞) Or {y | y ≥ -6}