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.
Work shown above! y = 148
Answer: x=20/3=6.67
Step-by-step explanation:
To solve proportions, the most useful way is to use [cross multiplication], where we not multiply horizontally but as diagonally.
-----------------------------------------------------------------------------
Given
x:10=9:6
Cross Multiply
9·x=6·10
9x=60
Divide 9 on both sides
9x/9=60/9
x=20/3=6.67
Hope this helps!! :)
Please let me know if you have any questions
Answer:
1. -2
2. 21^2
Step-by-step explanation:
Circumference of a circle:
C = 2 r π;
Length of an arc:
L = r π α / 180°
L = r π · 30° / 180° = r π /6
r π /6 : 2 r π = 1/6 : 2 = 1/12
Answer: A ) 1/12
