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Alex17521 [72]
3 years ago
7

e 400 trials in which the assistant maintained a neutral expression, the driver stopped in 229 out of the 400 trials. Find a 95%

confidence interval for the proportion of drivers who would stop when a neutral expression is maintained. In the 400 trials in which the assistant smiled at the driver, the driver stopped in 277 out of the 400 trials. Find a 95% confidence interval for the proportion of drivers who would stop when the assistant is smiling. What do your results in parts (a) and (b) suggest about the effect of a smile on a driver stopping at a pedestrian crosswalk? Explain briefly. (In Chapter 23, we will consider formal methods for comparing two proportions.)
Mathematics
1 answer:
Fittoniya [83]3 years ago
6 0

Answer:

Step-by-step explanation:

n = 400

Proportion p = 229/400= 0.5725

For 95% confidence interval we use Z value as 1.96

Std error = 0.025

margin of error = 1.96*0.025

Confidence interval 95% = 0.5725±Margin of error

= (0.524, 0.621)

b) When smiled x becomes 277

p = 0.6925

Std error = 0.023

Margin of error= 1.96*0.023

Confidence interval = (0.647, 0.738)

Smiling increases the chances of stopping since mean and conidence interval bounds are showing increasing trend.

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Please answer it’s 20 points for award!
guajiro [1.7K]

Answer:

The scale drawing is 20 units by 4 units

Step-by-step explanation:

20/5 = 4

100/5 = 20

6 0
3 years ago
In a group of 28 students, 12 study both Art and Biology.
MAVERICK [17]

Answer:

100%

Step-by-step explanation:

Use conditional probability:

P(B | A) = P(B and A) / P(A)

P(B | A) = (12/28) / P(A)

We need to find the probability that a student studies art.

P(A or B) = P(A) + P(B) − P(A and B)

24/28 = P(A) + (12+12)/28 − 12/28

P(A) = 12/28

P(B | A) = (12/28) / (12/28)

P(B | A) = 1

What this means is that all of the students who study art also study biology.

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3 years ago
We can define a propration as
coldgirl [10]
Comparative relationships between numbers
7 0
3 years ago
Read 2 more answers
-12.48 -(-2.99)-5.62
KATRIN_1 [288]

Answer:

-15.11

Step-by-step explanation:

-12.48-(-2.99)-5.62=\\-12.48+2.99-5.62=\\-9.49-5.62=\\-15.11

7 0
4 years ago
Read 2 more answers
There are five families that each have one child. Each of them hires Riley as a babysitter. Because the children she babysits ar
GREYUIT [131]

Answer:

Average Rate of Pay = $ 5.23 /hr

Step-by-step explanation:

We have a data in form of Hours of Baby Sitting and Amount of Pay. Since the Amount of pay depends upon the Hours of Baby Sitting. Thus, we take y = Amount of Pay, while x = Hours of Baby Sitting. So, the data becomes:

x (Hours) =   12      13      16      17       20

y ($)         =  54     56     65     64     100  

The statistical data calculated is:

∑x = 78,   ∑x² = 1258,   ∑y = 339,  ∑xy = 5504,   n = no. of data points = 5

Now, we use linear regression model to fit a straight line to this data.

y = a + bx   --------- eqn (1)

where,

b = [ n∑xy - ∑x.∑y]/[n∑x² -(∑x)²]

b = [ (5)(5504) - (78)(339)]/[(5)(1258) - (78)²]

b = 5.23

and,

a = (∑xy - b∑x²)/∑x

a = [5504 - (5.23)(1258)]/78

a = -13.83

Therefore, eqn (1) becomes:

<u>y = -13.83 + 5.23x</u>

The graph plot of this straight line fit is provided in the attachments.

Now, we derivate the equation with respect to x, to get the average rate of pay:

Average Rate of Pay = dy/dx = d/dx(-13.83 + 5.23x)

<u>Average Rate of Pay = $ 5.23 /hr</u>

8 0
3 years ago
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