Answer:
17.1≤x≤23.1
Step-by-step explanation:
The formula for calculating the confidence interval is expressed as;
CI = x ± z*s/√n
x is the mean yield = 20.1
z is the 80% z-score = 1.282
s is the standard deviation = 7.66
n is the sample size = 11
Substitute
CI = 20.1 ± 1.282*7.66/√11
CI = 20.1 ± 1.282*7.66/3.3166
CI = 20.1 ± 1.282*2.3095
CI = 20.1 ±2.9609
CI = (20.1-2.9609, 20.1+2.9609)
CI = (17.139, 23.0609)
hence the required confidence interval to 1dp is 17.1≤x≤23.1
Answer:

Step-by-step explanation:
We know i×i=i^2 which has value of -1.
We will multiply numerator and denominator by i so the denominator will no longer contain imaginary part(s).
Also multiplying by i/i does not change the value of the fraction because i/i=1.
Numerator × i gives (-5+i)i=-5i+i^2=-5i-1
=-1-5i.
Denominator × i gives (2i)i=2i^2=-2.
So the simplified version of this fraction given is:

The last simplification come from me multiplying fraction by -1/-1.
Answer:
1/8
Step-by-step explanation:
There are 3 + 3 + 6 = 12 marbles in the bag and 12 * 12 = 144 ways to choose two marbles when replacing. There are 3 * 6 = 18 ways to choose a red marble and then a blue marble so the probability is 18 / 144 = 1 / 8.
The circumference of the circle is = 2 x pi x 6 = 37.7cm
To find the arc = 360 divided by 169 = 2.13
The arc = 37.7 divided by 2.13 = 17.69 cm