Refer to the following normal curve to answer the questions below What percentage of the scores were between 60 and 75 points? percent
Question
Refer to the following normal curve to answer the questions below What percentage of the scores were between 60 and 75 points? percent
Solution
Para responder a esta pregunta, necesitamos conocer la media y la desviación estándar de la curva normal, así como los valores de 60 y 75 puntos en relación con estos parámetros. Sin esta información específica, podemos asumir que la curva normal es una distribución estándar con una media de 0 y una desviación estándar de 1, pero esto puede no ser correcto.
Sin embargo, si asumimos que la media es 67.5 y la desviación estándar es 7.5 (esto es solo un ejemplo), podemos proceder de la siguiente manera:
-
Calcular los valores Z:
- Para 60 puntos:
- Para 75 puntos:
-
Buscar los valores Z en la tabla de distribución normal:
- El valor Z de -1 corresponde aproximadamente al percentil 15.87%.
- El valor Z de 1 corresponde aproximadamente al percentil 84.13%.
-
Calcular el porcentaje entre los dos valores Z:
- Porcentaje entre 60 y 75 puntos = 84.13% - 15.87% = 68.26%
Por lo tanto, aproximadamente el 68.26% de las puntuaciones están entre 60 y 75 puntos, asumiendo que la media es 67.5 y la desviación estándar es 7.5. Si los valores reales de la media y la desviación estándar son diferentes, los cálculos cambiarán en consecuencia.
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