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3 years ago

tonya is 1.3 meters tall. she stands 7 meters in front of a tree and casts a shadow of 1.8 meters long. how tall is the tree

Mathematics

1 answer:

butalik [34]3 years ago

5 0

Answer:

The tree is 6.36 meters tall.

Explanation: Let AB is tree of height h t = ? and CD is Tonya h g = 1.3 meter tall at A C = 7 meters in front of tree . The shadow C E = 1.8 meters long . So two similar triangles are formed , one Δ A E B and other Δ C E D . So A B C D = A E C E or h t h g = A E A C or h t h g = A C + C E AC or h t 1.3 = 7 + 1.8 1.8 or h t = 8.8 ⋅ 1.3 1.8 ≈ 6.36 ( 2 d p )m

The tree is 6.36 meter tall.

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3 years ago

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Answer:

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If we compare the p value and the significance level for example $\alpha=1-0.99=0.01$ we see that $p_v$ so we can conclude that we have enough evidence to reject the null hypothesis.

And the best conclusion would be:

a) Yes. The counselor's claim is valid

Because we reject the null hypothesis in favor to the alternative hypothesis.

Step-by-step explanation:

Data given and notation

$\bar X=3.25$ represent the sample mean

$s=0.3$ represent the sample standard deviation

$n=36$ sample size

$\mu_o =3.1$ represent the value that we want to test

$\alpha$ represent the significance level for the hypothesis test.

t would represent the statistic (variable of interest)

$p_v$ represent the p value for the test (variable of interest)

State the null and alternative hypotheses.

We need to conduct a hypothesis in order to check if the mean is more than 3.1, the system of hypothesis would be:

Null hypothesis: $\mu \leq 3.1$

Alternative hypothesis: $\mu > 3.1$

If we analyze the size for the sample is < 30 and we don't know the population deviation so is better apply a t test to compare the actual mean to the reference value, and the statistic is given by:

$t=\frac{\bar X-\mu_o}{\frac{s}{\sqrt{n}}}$ (1)

t-test: "Is used to compare group means. Is one of the most common tests and is used to determine if the mean is (higher, less or not equal) to an specified value".

Calculate the statistic

We can replace in formula (1) the info given like this:

$t=\frac{3.25-3.1}{\frac{0.3}{\sqrt{36}}}=3$

P-value

The first step is calculate the degrees of freedom, on this case:

$df=n-1=36-1=35$

Since is a one right tailed test the p value would be:

$p_v =P(t_{(35)}>3)=0.00247$

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Answer:

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