How do you solve You earn 15n 15n dollars for mowing n lawns. How much do you earn for mowing one lawn? Seven lawns?
1 answer:
Answer:
$15 for a lawn, $105 for seven lawns.
Step-by-step explanation:
The question is about the direct ratio problem. Logically, you will earn more if you mow more lawn.
The scheme for this ratio is given below:
15 n_________n lawns
x_________ 1 lawn
You will earn 15 dollars for mowing a lawn
When you mow 7 lawns, the scheme will be in this manner:
15 n__________n lawns
x__________7 lawns
You will earn 105 dollars
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Answer:
And we can find this probability using the complement rule and we got:
Step-by-step explanation:
Previous concepts
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".
The Z-score is "a numerical measurement used in statistics of a value's relationship to the mean (average) of a group of values, measured in terms of standard deviations from the mean".
Solution to the problem
Let X the random variable that represent the weights of a population, and for this case we know the distribution for X is given by:
Where and
We are interested on this probability
And the best way to solve this problem is using the normal standard distribution and the z score given by:
If we apply this formula to our probability we got this:
And we can find this probability using the complement rule and we got:
Answer:
The critical values for α = 0.10 are t=±1.7341.
Step-by-step explanation:
The critical values for a two tailed test are the values of t that are placed in the limit of the significance level. If the test statistic t is greater than this critical values, the null hypothesis is rejected.
To determine this values, we first divide the significance level by 2. With a t-table or app, we can determine the t values for P(x>|t|)=α/2=0.05.
In this case, for a degrees of freedom DF=20-2=18, we have the test statistic t=±1.7341 that satisfies the condition.
Solution of the hypothesis test
In this problem we want to prove if the slope of the regression model is different from 0, by means of a hypothesis test.
First, we state the null and alternative hypothesis:
The significance level is .
The degrees of freedom for a simple regression model is:
The standard error estimated of the slope is 0.0053.
The test statistic t is calculated as:
The P-value for a two-tailed test for a t=4.0377 and DF=18 is:
The P-value is smaller than the significance level, so the effect is statistically significant. The null hypothesis is rejected.
