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
Pregunta completa:
Al llegar al hotel nos an dado un mapa con los lugares de la ciudad nos dijieron que 5 cm del mapa que representaban 600 metros de la realidad hoy queremos ir a un par que que se encuentra a 8 cm del hotel en el mapa. ¿A qué distancia del hotel está la pareja?
Respuesta: 960m
Explicación paso a paso:
Dado que:
5 cm en el mapa equivale a 600 m en tierra Por lo tanto,
8 cm en el mapa será equivalente a:
5 cm en el mapa - - - - - -> 600 m en el suelo 8cm - - - - - - -> y metros en el suelo
Usando la multiplicación cruzada
y × 5 = 8 × 600
5y = 4800 Luego,
y = 4800/5
y = 960m
Por lo tanto, 8 cm en el mapa serán 960 m en realidad.
Every number has its purpose in this case you start at -3 then the negative sign tells you which way you are going but since we have another negative sign in between the number we go to the right instead of left with that said you put the point in number 4
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