7 % of 39? need too know right now.

A car drives 50 miles in 40 minutes. how many miles does the car travel per minute

Anarel [89]

50 divided by 40 equals 1.25! So the car is going 1.25 mph

7 0

3 years ago

A forester studying diameter growth of red pine believes that the mean diameter growth will be different from the known mean gro

-Dominant- [34]

Answer:

$t=\frac{1.6-1.35}{\frac{0.46}{\sqrt{32}}}=3.07$

The degrees of freedom are given by:

$df =n-1= 32-1=31$

Since is a two-sided test the p value would be:

$p_v =2*P(t_{31}>3.07)=0.0044$

Since the p value is a very low value we have enough evidence to conclude that true mean is significantly different from 1.35 in/year at any significance level commonly used for example ( $\alpha=0.01,0.05, 0.1, 0.15$ ).

Step-by-step explanation:

Data given and notation

$\bar X=1.6$ represent the sample mean

$s=0.46$ represent the sample deviation

$n=32$ sample size

$\mu_o =1.35$ 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 true mean is different from 1.35 in/year, the system of hypothesis would be:

Null hypothesis: $\mu =1.35$

Alternative hypothesis: $\mu \neq 1.35$

The statistic is given by:

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

Calculate the statistic

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

$t=\frac{1.6-1.35}{\frac{0.46}{\sqrt{32}}}=3.07$

P-value

The degrees of freedom are given by:

$df =n-1= 32-1=31$

Since is a two-sided test the p value would be:

$p_v =2*P(t_{31}>3.07)=0.0044$

Since the p value is a very low value we have enough evidence to conclude that true mean is significantly different from 1.35 in/year at any significance level commonly used for example ( $\alpha=0.01,0.05, 0.1, 0.15$ ).

5 0

3 years ago

A square pyramid with a height of 7 inches has a volume of 47.25 cubic inches. Find the side length of the square base.

Romashka [77]

Answer:

4.5 inches

Step-by-step explanation:

volume= 1/3 (base area) × height

47.25= 1/3 ( base area) × 7

20.25 = base area

now since the base is a square we can evaluate base area = length²

20.25= length²

length = 4.5 inches

5 0

3 years ago

In a 24 km race, during which each runner maintains a constant speed throughout, Alice crosses the finish line while Becky is st

mr_godi [17]

Answer:6km

Step-by-step explanation:

Given

when Alice finishes the race Becky is 8km From finishing line

and caitlin 12 km from finishing line.

Suppose t is the time require by Alice to finish the race

and $V_a,V_b,V_c$ be the velocity of alice ,becky and caitlin

thus $t=\frac{24}{V_a}=\frac{24-8}{V_b}=\frac{24-12}{V_c}$

thus $\frac{V_b}{V_c}=\frac{4}{3}$

say t' is time required by beckey to complete 8 km thus

$V_b\times t'=8$

therefore for Caitlin

$V_c\times t'=\frac{8}{V_b}\times V_c=6$

Thus caitlin will cover a distance of 6 km in t' time and 6 km away from finishing.

7 0

3 years ago

A number decreased by fifteen is less than two.

Aliun [14]

Let us assume number of n.

The number is decreased by 15.

Decreasing by 15 means, we need to subtract 15 from that number.

So, it would be come n-15.

Now, it is said that the number would become less than 2.

So, we need to setup an inequality:

n-15 is less than 2.

Adding 15 on both sides, we get

n-15+15 < 2+15

n < 17.

<h3>So, we could say the number would be less than 17.</h3>

3 0

3 years ago