Q 3.3: In a survey, respondents chose between saying "cell phone" or "smartphone". The mean age of the respondents who chose "cell phone" is 39 and of those who chose "smartphone" is 34. The standard error for the difference between the means of both groups of the respondents is 2. What is the possible 95% confidence interval for the difference between the respondents who chose "cell phone" and respondents who chose "smartphone"

25

step-by-step explanation:

x = ±sqrt(10)

step-by-step explanation:

5 - 2x² = -15

subtract 5 from each side

5-5 - 2x² = -15-5

-2x^2   = -20

divide by -2 on each side

-2x^2   /-2= -20/-2

x^2 =10

take the square root on each side

sqrt(x^2 )=±sqrt(10)

x = ±sqrt(10)

check:

5 - 2x² = -15

+sqrt(10)

5 - 2(sqrt(10))² = -15

5 -2(10) = -15

5 -20 = -15

-15 = -15

-sqrt(10)

5 - 2(-sqrt(10))² = -15

5 -2(10) = -15

5 -20 = -15

-15 = -15

50-60=10

step-by-step explanation: