Answer:
3 cars
Step-by-step explanation:
If 12 cars are needed to carry 36 students,
<em>12</em><em>c</em><em>a</em><em>r</em><em>s</em><em> = 36</em>
the number of cars to carry 9 students will be:
xcars = 9
cross the two equations
36x = 12 X 9
36x = 108
x = 108/36
x= 3
Therefore, 3 cars are needed to carry 9 students
OR
12 cars will carry 36 students
so 1 car will carry, (36/12)students
therefore, 1 car will carry 3 students
So, for 9 students,
9students = 9/3 = 3
The inequality would be
0.75q ≥ 0.70(q+1)
q is defined as the number of questions he answers after the first one. We are told he gets 75% of those correct; 75%=75/100=0.75. This gives us 0.75q.
Since he gains proficiency on the exercises, the total number he gets correct has to be at least 70%. This means the inequality would have the symbol greater than or equal to, as it cannot be less and have him gain proficiency.
He has already answered 1 question and answers q more; this gives us a total of q+1. Since he gains proficiency, the cutoff was 70%; 70%=70/100=0.70. This gives us the expression 0.70(q+1).
Our total inequality would then be 0.75q ≥ 0.70(q+1)
Answer:
The correlation between hour of the day and the speed over the limit at which the motorist is ticketed is weak positive correlation.
Step-by-step explanation:
The correlation coefficient is a statistical degree that computes the strength of the linear relationship amid the relative movements of the two variables (i.e. dependent and independent).It ranges from -1 to +1.
The types of correlation coefficient are:
- +1 (-1) : Perfect positive (negative) correlation
- 0 to 0.30(-0.30) : Weak positive (negative) correlation
- 0.30(-0.30) to 0.70(-0.70) : Moderate positive (negative) correlation
- 0.70(-0.70) to 1 (-1) : Strong positive (negative) correlation
The correlation coefficient value between the hour of the day and the speed over the limit at which the motorist is ticketed is:
<em>r</em> = 0.12.
The value of <em>r</em> lies between:
0 < 0.12 < 0.30
Thus, the correlation between hour of the day and the speed over the limit at which the motorist is ticketed is weak positive correlation.
Answer:
The population standard deviation is not known.
90% Confidence interval by T₁₀-distribution: (38.3, 53.7).
Step-by-step explanation:
The "standard deviation" of $14 comes from a survey. In other words, the true population standard deviation is not known, and the $14 here is an estimate. Thus, find the confidence interval with the Student t-distribution. The sample size is 11. The degree of freedom is thus .
Start by finding 1/2 the width of this confidence interval. The confidence level of this interval is 90%. In other words, the area under the bell curve within this interval is 0.90. However, this curve is symmetric. As a result,
- The area to the left of the lower end of the interval shall be .
- The area to the left of the upper end of the interval shall be .
Look up the t-score of the upper end on an inverse t-table. Focus on the entry with
- a degree of freedom of 10, and
- a cumulative probability of 0.95.
.
This value can also be found with technology.
The formula for 1/2 the width of a confidence interval where standard deviation is unknown (only an estimate) is:
,
where
- is the t-score at the upper end of the interval,
- is the unbiased estimate for the standard deviation, and
- is the sample size.
For this confidence interval:
Hence the width of the 90% confidence interval is
.
The confidence interval is centered at the unbiased estimate of the population mean. The 90% confidence interval will be approximately:
.
He can make 140 different outfits