Honestly, I find Mrs. Garcia's method easier to perform mentally. It hinges on how familiar you are with your multiples of 5. (5*15 = 75 is a multiplication I often use)
Melissa's approach involves calculating 5*20 = 100 and 5*9 = 45, then combines the 3-digit result 100 with the 2-digit result 45, yielding 145. Adding 45 to 00 is simple and doesn’t require carrying digits, thus the arithmetic is fairly straightforward.
Mrs. Garcia's technique involves computing 5*14 = 70 and 5*15 = 75, then summing these two-digit results. Many people may not readily recall that 5*15=75, which complicates forming that product. The addition of 70 and 75 requires a carrying operation, making the math somewhat more complex. The resulting total is 145.
(The rationale behind my preference for Mrs. Garcia's method is that I can achieve the final sum by simply doubling 7 tens, followed by adding 5. The only 3-digit number to remember mentally is the ultimate total.)
_____Subtraction introduces a slight complication, yet reshaping it as $5(30 -1) = $150 - 5 = $145 is possible.
Or, you may reframe it as $5(28 +1) = $140 +5 = $145.
Dividing an even number by 2 to find the product of 5 is straightforward when you append a zero.
5*14 = 10*7 = 70
5*28 = 10*14 = 140.
Answer:
Indeed, having 15 people recognize the brand would be considered unusual, as it lies beyond 2 standard deviations from the average.
Step-by-step explanation:
Examine the provided data.
The average recognition rate for the Yummy brand name among groups is 12.5, with a standard deviation of 0.58.
Mean = μ= 12.5
σ = 0.58
n = 15
![\mu\pm2\sigma=12.5\pm 2(0.58)\\\mu\pm2\sigma=12.5\pm1.16\\\mu\pm2\sigma=[11.34, 13.66]](https://tex.z-dn.net/?f=%5Cmu%5Cpm2%5Csigma%3D12.5%5Cpm%202%280.58%29%5C%5C%5Cmu%5Cpm2%5Csigma%3D12.5%5Cpm1.16%5C%5C%5Cmu%5Cpm2%5Csigma%3D%5B11.34%2C%2013.66%5D)
Thus, having 15 people recognize the brand would indeed be unusual, as it is outside of the 2 standard deviations from the mean.
Answer: CI = (0, 8)
Step-by-step explanation: The confidence interval for the difference in means is given as
Lower limit
= (x1 - x2) + margin of error
Upper limit
= (x1 - x2) - margin of error
Where x1 - x2 = 8 and the margin of error = 8
For the lower limit,
= 8 - 8 = 0
For the upper limit
= 8 + 8 = 16
Thus, CI = (0, 8)
Detailed explanation:
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