which sequences are arithmetic? check all that apply. –8.6, –5.0, –1.4, 2.2, 5.8, … 2, –2.2, 2.42, –2.662, 2.9282, … 5, 1, –3, –
sergiy2304 [10]
In an arithmetic sequence, the next term is found by adding a constant term to each number to arrive at the next number. The common difference can be found by subtracting the first term from the second term.
-8.6, -5.0, -1.4, 2.2, 5.8....the common difference here is 3.6
-8.6 + 3.6 = -5.0
-5.0 + 3.6 = -1.4
1.4 + 3.6 = 2.2
2.2 + 3.6 = 5.8
so this IS an arithmetic sequence.
2,-2.2, 2.42, -2.662, 2.9282...there is no common difference..so this is not an arithmetic sequence
5,1,-3,-7,-11....common difference is -4
5 + (-4) = 1
1 + (-4) = -3
-3 + (-4) = -7
-7 + (-4) = -11
this IS an arithmetic sequence
-3,3,9,15,21...common difference is 6
-3 + 6 = 3
3 + 6 = 9
9 + 6 = 15
15 + 6 = 21
this IS an arithmetic sequence
-6.2, -3.1, -1.55, -0.775, -0.3875...this is not an arithmetic sequence
The equation that best models this situation would be: y=40+30x
Answer:
Mean = 78.2
Standard deviation = 5.8
Step-by-step explanation:
Mathematically z-score;
= (x-mean)/SD
From the question;
12% of test scores were above 85
Thus;
P( x > 85) = 12%
P(x > 85) = 0.12
Now let’s get the z-score that has a probability of 0.12
This can be obtained from the standard normal distribution table and it is = 1.175
Thus;
1.175 = (85 - mean)/SD
let’s call the mean a and the SD b
1.175 = (85-a)/b
1.175b = 85 - a
a = 85 - 1.175b ••••••••(i)
Secondly 8% of scores were below 70
Let’s find the z-score corresponding to this proportion;
We use the standard normal distribution table as usual;
P( x < 70) = 0.08
z-score = -1.405
Thus;
-1.405 =( 70-a)/b
-1.405b = 70-a
a = 70 + 1.405b ••••••(ii)
Equate the two a
70 + 1.405b = 85 - 1.175b
85 -70 = 1.405b + 1.175b
15 = 2.58b
b = 15/2.58
b = 5.81
a = 70 + 1.405b
a = 70 + 1.405(5.81)
a = 78.16
So mean = 78.2 and Standard deviation is 5.8
Answer:
About 425
Step-by-step explanation:
Tell me if you want the explanation.
