[機統] 請問一題統計

[strekm (丁丁是念來過倒)]

A lumber company has claimed that the standard deviation for the lengths of
their 6 foot boards is 0.5 inches or less.  To test their claim, a random
sample of 17 six- foot boards is selected; and it is determined that the
standard deviation of the sample is 0.4.  Do the results of the sample
support the company's claim?  Use α = 0.1.

Answer: Since X^2 = 25 > 23.54, reject Ho
p-value is between .05and0.10

請問 為什麼X^2是25阿

我怎麼算都是10.24 可是好多地方的解答都是25

感謝

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→ andrew43    : 解答明顯錯了。觀測值都已符合H0了，怎可能拒絕之？
→ andrew43    : 25 是 0.5^2 * 16 / (0.4^2)，解答誤值數字了。
→ strekm      : 感恩！