問95
頻出度★★★
A さんは，製品 N の売上の動向を分析するため，昨年と今年の売上高の推移を基に，表計算ソフトを用いて図1のワークシートを作成した。 図1の D 列の移動合計欄には，当該月を含む過去12か月の売上の合計を，E 列の売上累計欄には今年の売上高の累計を計算する式が入力されている。また，製品 N の売上の動向を視覚的に確認するため，図2の売上高の推移グラフを作成した。 図1及び図2から読み取れる製品N の売上の分析として, 適切なものはどれか。
平成25年度 春期 ITパスポート試験 問95
ストラテジ系企業活動 › 業務分析・データ利活用
This question's explanation and your answers so far.
解説
問 95
Incorrectア
The peak of monthly sales is not August (9,200 thousand yen) but March (13,200 thousand yen), so the premise itself does not match Figure 1. Moreover, the moving total, which shows the momentum of growth, keeps rising after August's 65,200 thousand yen: 66,000 in September → 67,500 in October → 68,900 in November → 70,300 thousand yen in December, and the increases stay at 800 to 1,500 thousand yen without shrinking. The figures give no basis for saying that growth slowed after August.
Incorrectイ
The slope of the cumulative sales line (column E) represents the sales of that month itself. In March it rises steeply with 13,200 thousand yen, while at 3,700 thousand yen in June and 4,100 thousand yen in December it becomes gentle, so the slope is not constant. In Figure 2 the cumulative line is also S-shaped, climbing sharply around March and flattening out in June and July, so the statement that monthly sales fluctuate little is wrong.
Incorrectウ
This year's sales fall sharply from 13,200 thousand yen in March to 7,700 thousand yen in April, and keep decreasing after that: 6,500 in May → 3,700 in June → 3,500 thousand yen in July. From September onward as well, 5,800 in September → 4,700 in October → 4,300 in November → 4,100 thousand yen in December, one month after another comes in below the previous month, so sales did not continuously increase over the previous month throughout the year.
- エ
正解 The correct answer is エ. Column D in Figure 1, the moving total, is the sum of sales for the past 12 months including that month, and it smooths out seasonal ups and downs to show the long-term momentum. Its value keeps rising every month: 60,800 in January → 62,400 in March → 65,200 in August → 70,300 thousand yen in December. The upper line indicated by (a) in Figure 2, which looks almost flat, is in fact sloping gently upward when examined closely. The annual total also grew from 60,600 thousand yen last year to 70,300 thousand yen this year. On the other hand, column C, this year's sales, has peaks of 13,200 thousand yen in March and 9,200 thousand yen in August but falls to 4,100 thousand yen in December, so the month-to-month swings are large. Reading these two together gives “although there is monthly fluctuation, growth is continuing when viewed over the long term”, so エ is consistent with the figures.
ここがポイント
- A Z chart (sales trend graph) is read from three lines: monthly sales, cumulative sales, and the moving total. Monthly sales show seasonal fluctuation; cumulative sales are the running total from the start of the period (its slope equals each month's sales); the moving total is the sum of the past 12 months and shows the long-term trend.
- If the moving total line slopes upward to the right, judge it as long-term growth; flat means level; sloping downward to the right means shrinking. The key point is not to draw conclusions about growth momentum from a single month's rise or fall, or from a single month's peak alone.
用語