A store owner bought some flower pots for $1,200. The flower pots were sold for $2,700, with a profit of $30 per pot. How many f
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Answer:
Inequality:
Inequality solved:
The graph is attached.
Step-by-step explanation:
You need to remember the meaning of the inequalities symbols:
: Less than.
: Greater than.
: Less than or equal to.
: Greater than or equal to.
Let be "x" the number of more songs Carlotta can download.
According to the information given in the exercise, she can download no more than 12 song files per week. This indicates that you must use the symbol .
Since she has already downloaded 10 song files this week, you can write the following inequality that represents this situation:
In order to solve it, you must subtract 10 from both sides:
Plot this result on a number line.
Since the symbol of the inequality is , the dot must be filled (Observe the number line attached).
Answer:
So on this case the 95% confidence interval would be given by (15.641;18.359)
And since the lower limit for the confidence interval is higher than 15 we can conclude that at 5% of significance the true mean is higher than 15 cm
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".
represent the sample mean
population mean (variable of interest)
s=1.9 represent the sample standard deviation
n=10 represent the sample size
Confidence interval
The confidence interval for the mean is given by the following formula:
(1)
In order to calculate the critical value we need to find first the degrees of freedom, given by:
Since the Confidence is 0.95 or 95%, the value of and
, and we can use excel, a calculator or a table to find the critical value. The excel command would be: "=-T.INV(0.025,9)".And we see that
Now we have everything in order to replace into formula (1):
So on this case the 95% confidence interval would be given by (15.641;18.359)
And since the lower limit for the confidence interval is higher than 15 we can conclude that at 5% of significance the true mean is higher than 15 cm