Help me, please i im failing maath 41 f

2c(b+15c)+(b–6c)(5c+2b)

ArbitrLikvidat [17]

Answer: 2b^2 - 5bc

Work is shown below

7 0

3 years ago

Suppose a sample of 100 families of four vacationing at Niagara Falls resulted in sample mean of $282.45 spent per day and a sam

Juli2301 [7.4K]

Given Information:

Mean = μ = $282.45

Standard deviation = σ = $64.50

Sample size = n = 100

Confidence level = 95%

Required Information:

95% Confidence interval = ?

Answer:

95% Confidence interval = ($269.81, $295.09)

Step-by-step explanation:

We are given a Normal Distribution, which is a continuous probability distribution and is symmetrical around the mean. The shape of this distribution is like a bell curve and most of the data is clustered around the mean. The area under this bell shaped curve represents the probability.

What is Confidence Interval?

The confidence interval represents an interval that we can guarantee that the target variable will be within this interval for a given confidence level.

The confidence interval is given by

$CI = \bar{x} \pm MoE\\$

Where $\bar{x}$ is the mean and MoE is the margin of error given by

$MoE = z_{\alpha/2}(\frac{\sigma}{\sqrt{n} } ) \\$

Where σ is the standard deviation, n is the sample size and $z_{\alpha/2}$ is the z-score corresponding to 95% confidence level.

$z_{\alpha/2} = 1 - 0.95 = 0.05/2 = 0.025\\\\z_{0.025} = 1.96$

$MoE = 1.96\cdot \frac{64.50}{\sqrt{100} } \\\\MoE = 1.96\cdot 6.45\\\\MoE = 12.64\\$

Finally, the confidence interval is

$CI = \bar{x} \pm MoE\\\\CI = 282.45 \pm 12.64\\\\CI = 282.45 - 12.64 \: and \: 282.45 + 12.64\\\\CI = \$269.81 \: and \:\:\$295.09\\$

Therefore, we are 95% sure that the true population mean amount spent per day by a family of four visiting Niagara Falls is within the interval of ($269.81, $295.09)

3 0

3 years ago

Biologists studying wildlife in the state parks want to estimate the average weight of chipmunks. They measured the weights of 5

bazaltina [42]

Answer:

The average weight of the chipmunks is 91 grams

Step-by-step explanation:

The mean of a dataset gives the average which is obtained by taking the sun of each data value and dividing by the number of samples. The median however requires the arrangement of data in terms of size ze (ascending) and taking the mid value (value which falls in the 50% mark). For the data above, the most appropriate measure of the average is the mean. Hence, the prediction which matches the data is ; The average weight of the chipmunks is 91 grams.

7 0

2 years ago

Read 2 more answers

Sally is having a problem with her puppy leaving the yard so she decides to build a new fence. The length of the yard is 8 feet

Rufina [12.5K]

Please check the attached file for the diagram of Sally's yard.

Let $w$ be the width of the yard.

Let $l$ be the length.

We are given that the length of the yard is 8 feet more than 4 times the width. Let us convert this into a mathematical equation.

4 times the width will be $4w$ . Now, 8 feet, or 8 more than 4 times the width will be $4w+8$ . We know that this is the value of the length of the yard and thus we can write this as:

$l=4w+8$

As we can see we have found the relationship between the length, $l$ and the width, $w$ of the yard.

We have been told that the total length of the fence required for the yard is 106 feet. This obviously means that the perimeter of the rectangular yard is 106 feet.

Now, we know that the perimeter of a rectangle is given by:

Perimeter= $2(l+w)=2((4w+8)+w)$ this is because we know that the length, $l$ is given by $l=4w+8$ .

Continuing further we get:

$106=8w+16+2w=10w+16$ This is because Perimeter=length of the fence=106 (given)

Therefore, $10w=90$

or, $w=9$ so, we just now found the width of the yard which is 9 feet. We are required to find the length. We can easily find the length using the relationship between $w$ and $l$ which is:

$l=4w+8$ giving us:

$l=4\times9+8=44$

Thus the length of the fence is 44 feet.

5 0

3 years ago

The ground temperature at an airport is 12 °C. The temperature decreases by 5.4 °C for every increase of 1 kilometer above the g

olga_2 [115]

Decrease in the temperature: 5.4×5=27°C

Final temperature: 12-27=-15°C

6 0

3 years ago