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1 year ago

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The score of golfers for a particular course follows a normal distribution that has a mean of 73 and a standard deviation of 3.

Suppose a golfer played the course today. Find the probability that her score is at least 74. 0.4772

1 answer:

Artemon [7]1 year ago

3 0

Answer:

P(X $\geq$ 74) = 0.3707

Step-by-step explanation:

We are given that the score of golfers for a particular course follows a normal distribution that has a mean of 73 and a standard deviation of 3.

Let X = Score of golfers

So, X ~ N( $\mu=73,\sigma^{2}=3^{2}$ )

The z score probability distribution is given by;

Z = $\frac{X-\mu}{\sigma}$ ~ N(0,1)

where, $\mu$ = population mean = 73

$\sigma$ = standard deviation = 3

So, the probability that the score of golfer is at least 74 is given by = P(X $\geq$ 74)

P(X $\geq$ 74) = P( $\frac{X-\mu}{\sigma}$ $\geq$ $\frac{74-73}{3}$ ) = P(Z $\geq$ 0.33) = 1 - P(Z < 0.33)

= 1 - 0.62930 = 0.3707

Therefore, the probability that the score of golfer is at least 74 is 0.3707 .

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A new curing process developed for a certain type of cement results in a mean compressive strength of 5000 kilograms per square

Sedbober [7]

Answer:

$\alpha =0.0668$

Step-by-step explanation:

Data given and notation

The info given by the problem is:

$n=25$ the random sample taken

$\mu =5000$ represent the population mean

$\sigma =100$ represent the population standard deviation

The critical region on this case is $\bar X$ so then if the value of $\bar X \geq 4970$ we fail to reject the null hypothesis. In other case we reject the null hypothesis

Null and alternative hypotheses to be tested

We need to conduct a hypothesis in order to determine if the true mean is 5000, the system of hypothesis would be:

Null hypothesis: $\mu = 5000$

Alternative hypothesis: $\mu \neq 5000$

Let's define the random variable X ="The compressive strength".

We know from the Central Limit Theorem that the distribution for the sample mean is given by:

$\bar X \sim N(\mu , \frac{\sigma}{\sqrt{n}})$

Find the probability of committing a type I error when H0 is true.

The definition for type of error I is reject the null hypothesis when actually is true, and is defined as $\alpha$ the significance level.

So we can define $\alpha$ like this:

$\alpha= P(Error I)= P(\bar X$

And in order to find this probability we can use the Z score given by this formula:

$Z=\frac{\bar X -\mu}{\frac{\sigma}{\sqrt{n}}}$

And the value for the probability of error I is givn by:

$\alpha= P(\bar X$

4 0

1 year ago

Ben and Josh went to the roof of their 40-foot tall high school to throw their math books offthe edge.The initial velocity of Be

Taya2010 [7]

Answer

Josh's textbook reached the ground first

Josh's textbook reached the ground first by a difference of $t=0.6482$

Step-by-step explanation:

Before we proceed let us re write correctly the height equation which in correct form reads:

$h(t)=-16t^2 +v_{o}t+s$ Eqn(1).

Where:

$h(t)$ : is the height range as a function of time

$v_{o}$ : is the initial velocity

$s$ : is the initial heightin feet and is given as 40 feet, thus Eqn(1). becomes:

$h(t)=-16t^2 + v_{o}t + 40$ Eqn(2).

Now let us use the given information and set up our equations for Ben and Josh.

<u>Ben:</u>

We know that $v_{o}=60ft/s$

Thus Eqn. (2) becomes:

$h(t)=-16t^2+60t+40$ Eqn.(3)

<u>Josh:</u>

We know that $v_{o}=48ft/s$

Thus Eqn. (2) becomes:

$h(t)=-16t^2+48t+40$ Eqn. (4).

<em><u>Now since we want to find whose textbook reaches the ground first and by how many seconds we need to solve each equation (i.e. Eqns. (3) and (4)) at </u></em> $h(t)=0$ <em><u>. Now since both are quadratic equations we will solve one showing the full method which can be repeated for the other one. </u></em>

Thus we have for Ben, Eqn. (3) gives:

$h(t)=0-16t^2+60t+40=0$

Using the quadratic expression to find the roots of the quadratic we have:

$t_{1,2}=\frac{-b+/-\sqrt{b^2-4ac} }{2a} \\t_{1,2}=\frac{-60+/-\sqrt{60^2-4(-16)(40)} }{2(-16)} \\t_{1,2}=\frac{-60+/-\sqrt{6160} }{-32} \\t_{1,2}=\frac{15+/-\sqrt{385} }{8}\\\\t_{1}=4.3276 sec\\t_{2}=-0.5776 sec$

Since time can only be positive we reject the $t_{2}$ solution and we keep that Ben's book took $t=4.3276$ seconds to reach the ground.

Similarly solving for Josh we obtain

$t_{1}=3.6794sec\\t_{2}=-0.6794sec$

Thus again we reject the negative and keep the positive solution, so Josh's book took $t=3.6794$ seconds to reach the ground.

Then we can find the difference between Ben and Josh times as

$t_{Ben}-t_{Josh}= 4.3276 - 3.6794 = 0.6482$

So to answer the original question:

<em>Whose textbook reaches the ground first and by how many seconds?</em>

Josh's textbook reached the ground first
Josh's textbook reached the ground first by a difference of $t=0.6482$

3 0

1 year ago

The total amount paid on a 35 year loan was $98,000. If the interest rate was 4.1% and compounded monthly, what was the principa

Levart [38]

Answer:

The principal amount was $23,393.45

Step-by-step explanation:

The total amount paid on a 35 year loan was $98,000 at the rate of interest 4.1%

We will calculate Principal amount by this formula

$A=P(1+\frac{r}{n})^{nt}$

Where A = amount (98,000)

P = Principal amount (P)

r = rate of interest 4.1% (0.041)

n = number of compounding interest monthly (12)

t = time (35 years)

$98,000=P(1+\frac{0.041}{12})^{(12)(35)}$

$98,000=P(1+0.003416)^{(420)}$

$98,000=P(1.003416)^{(420)}$

98,000 = P(4.189386)

= 4.189386P = 98,000

P = $\frac{98000}{4.189386}$

P = 23,392.4494 ≈ $23,392.45

The principal amount was $23,393.45

5 0

2 years ago

Read 2 more answers

1. Write an exponential function to represent the spread of Ben's social media post. 2. Write an exponential function to represe

Alex777 [14]

Answer:

1. y = 2(3)ˣ; 2. y = 10(4)^x; 4. Amber = 192 and 3 145 728;

Ben has 54 and 11 098; Carter = 80 and 10 249 shares;

5. Shifted up 45 shares; 6. Amber's;

7. Fewer friends. more shares.

Step-by-step explanation:

The general equation for an exponential function is

y = a(b)ˣ

1. Ben's function

The initial value a = 2.

6 = 2(b)¹ = 2b

Ben's function is

y = 2(3)^x

2. Carter's function

Carter shared his post with 10 friends on Day 0, so a= 10.

Each friend shared with 2 people each day, so b = 2.

Therefore, Carter's function is

y=10(2)ˣ

3. Graphs

$\begin{array}{cccc}& \textbf{Amber} &\textbf{Ben} & \textbf{Carter}\\\mathbf{x} & \mathbf{3(4)^{x}} &\mathbf{2(3)^{x}} & \mathbf{10(2)^{x}}\\0 & 3 & 2 & 10\\1 & 12 & 6 & 20\\2 & 48 & 18 & 40\\3 & 192 & 54 & 80\\\end{array}$

The figure below shows the graphs for each function.

4. Predictions

(a) Amber

(i) Day 3

y = 3(4)³ = 3 × 64 = 192

(ii) Day 10

y = 3(4)¹⁰ = 3 × 1 048 576 = 3 145 728

(b) Ben

(i) Day 3

y = 2(3)³ = 2 × 27 = 54

(ii) Day 10

y = 2(3)¹⁰ = 2 × 29 049 = 118 098

(c) Carter

(i) Day 3

y = 10(2)³ = 10 × 8 = 80

(ii) Day 10

y =10(2)¹⁰ = 10 × 1024 = 10 240

5. Sharing with assisted living facility

y = 3(4)ˣ + 45

The new graph will be shifted up by 45 units.

6. Fastest post

Amber's post travels the fastest.

After only two days, she already has more posts than anyone else.

By Day 10, she has more than 25 times the shares of her closest competitor.

7. Preference

It's not the number of friends you have, but the number of shares they make, that is the important factor.

Carter started with 10 friends, but they made only two shares.

Amber started with only three friends, but they made four shares. By Day 3, she had 192 shares compared to 82 for Carter and only 54 for Ben

If I had to choose, I would prefer a post with fewer friends initially but more shares, like Amber.

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1 year ago

Which describes how to graph h (x) = negative RootIndex StartRoot x + 8 EndRoot by transforming the parent function?

SashulF [63]

Answer:

Reflect the parent function over the x-axis, and translate it 8 units to the left.

Step-by-step explanation:

The given function is

$y = - \sqrt{x + 8}$

The parent function is

$y = \sqrt{x}$

Since there is a negative multiply the transformed function, there is a reflection in the x-axis.

Since 8 is adding, within the square root, there is a horizontal translation of 8 units to the left.

Therefore to graph the given function, reflect the parent function over the x-axis, and translate it 8 units to the left.

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